GB2626002A

GB2626002A - Exercise system

Info

Publication number: GB2626002A
Application number: GB2300132.4A
Authority: GB
Inventors: Olstad Daniela; Luomala Matti
Original assignee: Polar Electro Oy
Current assignee: Polar Electro Oy
Priority date: 2023-01-05
Filing date: 2023-01-05
Publication date: 2024-07-10
Also published as: EP4646145A1; WO2024146982A1

Abstract

A method of determining a desired rest period for a phosphagen regime physical activity of a user comprises determining an end of the physical activity 42 and the start of a rest period 44 of the user and measuring an oxygen consumption during the rest period; the method determines whether said oxygen consumption meets one or more predetermined parameters 48 and an indication is provided if the one or more parameter is met 50. The oxygen consumption may be measured by measuring heart rate activity including stroke volume and heart rate. Also disclosed is a device for achieving the method and a method of determining a rest period by measuring ventilation of a user.

Description

Exercise system The present disclosure relates to a system for exercise, in particular, but not limited to, a system for determining a rest period for physical a activity.

Background of the Invention

During short periods of exercise or physical activity, the body uses the "phosphagen" system to generate energy for muscle movement. In such a system, the body uses adenosine triphosphate (ATP) and phosphocreatine (PCr) already provided in the muscles to provide energy. During subsequent rest, the body regenerates ATP. The user may then perform further exercise when the ATP is at least partially regenerated. In contrast, during longer periods of exercise, the body uses glycolytic energy sources (i.e. aerobic or anaerobic) to generate energy for the muscles. Thus, it can be seen that different lengths of exercise use a different energy generation regime. When the primary energy source of the exercise is the phosphagen system, the exercise can be called a phosphagen regime exercise. Work periods or equivalently activity periods of such an exercise are typically very short, e.g. below 30 seconds or below 15 seconds or even below ten seconds. A rest period is provided between consecutive activity periods to allow regeneration of the energy reserves for the next activity period.

In order to exercise effectively, it is beneficial to accurately determine the extent of the rest period, in particular, as the length of rest period can determine the desired training effect. For example: for increasing strength and power, 2-5 minutes is optimal; to increase hypertrophy (muscle growth), 30-90 seconds is optimal; and to increase endurance, 30 seconds or less is optimal. For a sprint runner, the rest period may be even 10, 15, or 20 minutes between consecutive sprints. However, these parameters are variable between different users, for example, due to different physiologies. In the context of strength and other short-termed maximum intensity exercises, the purpose is often to increase the strength and power, so the aim may be to find the optimal rest period within those 2-5 minutes.

Prior art solutions simply use predetermined rest periods. Such predetermined values are not personalised, and so may not be able suitable for every user. This may provide suboptimal results for the desired training effect. A second prior art solution uses heart rate recovery (i.e. a normalisation of the heart rate), however, the correlation between heart rate and ATP regeneration is poor, and thus does not provide adequate determination of the optimal rest period.

The present invention aims to overcome or ameliorate one or more of the above problems, in particular, to provide a means to accurately determine the optimal duration of the rest period following the activity period of a phosphagen 15 regime exercise.

Statement of Invention

According to a first aspect of the invention, there is provided: a method of determining a desired rest period for a phosphagen regime physical activity of a user, comprising: determining an end of the physical activity and the start of a rest period of the user; measuring an oxygen consumption of the user during the rest period; and determining whether said oxygen consumption meets one or more predetermined parameter. The method may further include providing an indication if the parameter is met.

The oxygen consumption may be measured by measuring heart activity of the user, the heart activity comprising a heart stroke volume and a heart rate of the user and by determining the oxygen consumption based on said measured heart stroke volume and heart rate. The heart activity may be measured using electrocardiogram (ECG) and/or bioimpedance (impedance cardiography). The heart activity may be measured using two or more electrodes. The electrodes may be provided on or around the user's heart, e.g. in skin contact at a thoracic region of the body. The ECG may be measured from any suitable location of the user's body. Some ECG measurement devices may be incorporated into wrist devices, for example. The oxygen consumption may be determined by measuring oxygen via inhalation (e.g. using a portable oxygen consumption device).

The method may comprise providing an indication if the parameter is met. The method may comprise providing a notification to the user (i.e. directly thereto) if the parameter is met. The notification may be provided on a processing unit. The processing unit may be wearable by the user. The processing unit may comprise a watch or other wrist mounted device. The notification may comprise an indication to the user to maintain a rest period and/or to end a rest period. The notification may comprise an indication to the user to begin a subsequent physical activity.

The predetermined parameter may comprise an absolute value of oxygen consumption, e.g. an oxygen consumption threshold. The predetermined parameter may comprise a rate of change (i.e. differential) of the oxygen consumption, e.g. a threshold rate of change. The predetermined parameter may comprise a characteristic curve, shape or pattern of the oxygen consumption with respect to time.

The method may comprise providing a resting oxygen consumption, and where the predetermined parameter comprises a ratio of the measured oxygen consumption and the resting oxygen consumption.

The method may comprise measuring a maximum oxygen consumption during the activity, and where the predetermined parameter comprises a fraction of the maximum oxygen consumption.

The predetermined parameter may comprise a threshold oxygen consumption and the method may comprise determining whether the measured value of oxygen consumption is above or below said value. The method may comprise performing a first action if the measured value of oxygen uptake is above said threshold. The method may comprises performing a second action if the measured value of oxygen uptake is below said threshold.

One of the first and second action may be to indicate to a user to maintain the rest period and/or the other of the first and second action is an indication to the user of readiness to start a next activity period.

The notification may comprise an audible, visual and/or tactile notification.

The method may comprise providing a selection of an exercise/activity type. The oxygen consumption parameter may be variable in accordance with said exercise/activity type. The parameter may be determined based on desired to training effect or benefit, e.g. whether the exercise/activity is to increase muscle strength, hypertrophy, and/or endurance.

The length and/or intensity of the activity may be indicated to the user before said activity in accordance with said activity type. The end of the activity period 15 may be determined in accordance with said activity type length.

If the activity type is a first activity type, the method may comprise said determining whether said oxygen consumption meets said one or more predetermined parameter and providing the indication, if the parameter is met.

Else if the activity type is a second activity type, the method comprises determining whether a measured heart activity meets a predetermined heart activity threshold, and providing the indication, if the heart activity threshold is met.

The oxygen consumption parameter may be variable in accordance with one or more predetermined physiological variable of the user. The physiological variable may comprise one or more of: weight; height; age; sex; or general fitness level of the user.

The method may comprise measuring ventilation of the user. The method may comprises determining whether said ventilation meets one or more predetermined parameter.

The method may comprise providing a notification to the user if the ventilation 35 parameter is met. The notification may indicate to end a rest period and to start the next period of physical activity, e.g. the next sprint or the next maximum strength exercise interval.

The method may comprise providing a notification to user when either the oxygen uptake value parameter or ventilation parameter is met. The method may comprise providing a notification to user when both the oxygen uptake value parameter and ventilation parameter are met.

The period of activity may be less than or equal to 30 seconds. The period of 10 activity may be less than or equal to 15 seconds. The period of activity may be less than or equal to 10 seconds.

The method may comprise measuring heart activity during the physical activity. The method may comprise determining an end of the physical activity if said 15 heart activity measurement meets one or more parameter.

The rest period is less than or equal to 15 minutes. The rest period is less than or equal to ten minutes. The rest period is less than or equal to five minutes.

The rest period may be indicative of partial or complete ATE' regeneration.

Heart activity may be measured in real time. The notification may be provided in real time.

According to a further aspect, there is provided: a computer program or 25 computer readable medium comprising program instructions which, when executed by the computer, cause the computer to carry out a computer process implementing the method according to any preceding claim.

According to a further aspect, there is provided: a device configured to determine a desired rest period for a phosphagen regime physical activity of a user, and comprising a controller configured to: determine an end of the physical activity and the start of a rest period of the user; receive measurements oxygen consumption during the rest period; and determine whether said oxygen consumption meets one or more predetermined parameter.

The device may be operatively connected to a plurality of electrodes to provide said heart activity measurements. The device may be configured to provide an indication if the parameter is met. The device may be configured to provide a notification to the user (i.e. directly thereto) if the parameter is met.

According to a further aspect, there is provided: a wearable device comprising the device according to the previous aspect. The wearable device may be wrist or arm device.

According to a further aspect, there is provided: a method of determining a desired rest period for a phosphagen regime physical activity of a user, comprising: determining an end of the physical activity and the start of a rest period of the user; measuring the ventilation of the user during the rest period.; determining a ventilation value based on said measured ventilation; and determining whether said ventilation meets one or more predetermined parameter.

The ventilation measurements may comprise measuring a breathing rate and tidal volume of the user. In an embodiment, the tidal volume is assumed to be 20 constant and the ventilation measurements comprise measuring the breathing rate and estimating the ventilation without the tidal volume measurements.

The predetermined parameter may comprise an absolute value of the measured ventilation. The predetermined parameter may comprise a rate of change (i.e. differential) of the ventilation. The predetermined parameter may comprise a total ventilation (i.e. integral of the ventilation). The predetermined parameter may comprise a characteristic curve, shape or pattern of the measured ventilation with respect to time.

According to a further aspect, there is provided: a device configured to determine a desired rest period for a phosphagen regime physical activity of a user, and comprising a controller configured to: determine an end of the physical activity and the start of a rest period of the user; receive measurements of the ventilation of the user during the rest period, the ventilation comprising a breathing rate and tidal volume of the user; determine a ventilation value based on said measured breathing rate and tidal volume; and determine whether said ventilation meets one or more predetermined parameter.

Any aspect of the invention may be combined with any other aspect of the 5 invention where practicable.

Detailed description

Embodiments of the present invention are described below, by way of example 10 only, with reference to the accompanying drawings: Figure 1 shows a schematic view of an electrode arrangement of an exercise monitoring device; Figure 2 shows a schematic view of an wrist watch of the exercise 15 monitoring device; Figure 3 shows a schematic view an ATP regeneration regime; Figure 4 shows a first schematic view of an oxygen consumption regime; Figure 5 shows a second schematic view of an oxygen consumption regime; Figures 6-8 show a schematic view of a monitoring regime for the exercise monitoring device.

An exercise monitoring device 2 is shown in figure 1. The device 2 is configured to be worn other otherwise provided on a user 4. In some embodiments, the device 2 is embedded in clothing, garment, apparel, or the like. In other embodiments, the device 2 may be provided as a separate piece (e.g. mounted via a strap or the like). It can be appreciated that the exact device is not pertinent to the invention at hand. The monitoring device may have the capability of measuring the user's oxygen uptake and/or ventilation or at least to process such measurement data according to the embodiments described herein. An example of such a monitoring device is described in WO 2019/238599, incorporated herein by reference. There exist other portable measurement devices capable of measuring the oxygen uptake and/or ventilation, some of which have been validated in scientific studies. In the following, the device 2 is based on stroke volume measurements but equally another state-of-the-art measurement device may be used for measuring the oxygen consumption and/or ventilation.

The device 2 comprises a plurality of electrodes 4. The electrodes 4 are connected via a wire 6 or the like. In some embodiments, the electrodes may communicate wirelessly. The electrodes are generally spread across the user's chest area. At least one of the electrodes is provided at the heart area and at least electrode is provided below the heart area. The system is configured to use a combination of bioimpedance and/or electrocardiogram (ECG) to determine a heart stroke volume of the user (i.e. the volume of blood ejected from the ventricle with each cardiac cycle). The process will not be discussed in detail and is performed using the method described in W0'599.

The device 2 comprises a processing unit 8 configured to process data collected by the electrodes 4. As shown in figure 2, the processing unit may be provided by device wearable on the user's wrist, forearm and/or upper arm. The processing unit 8 may be provided on a watch, "smart watch" or other wrist mounted device. The device 2 comprises a strap 10 to allow releasable attachment to the user. The device 2 comprises a display 12 to allow viewing of data measured or processed by the device. The display 12 may display other external parameters, for example, the date or time etc. The device 2 may comprise a one or more input 14. The input may comprise one or more manual input, such as a button/switch or the like. In some embodiments, the input may be provided by a touch sensor (e.g. provided by the display 12).

The processing unit 8 is operatively connected to the electrodes 4. Typically, this is provided by a wireless connection, for example, Bluetooth (RTM), Wifi, or other local area network or personal area network wireless connection. In other embodiments, the electrodes and processing unit may be connected via wires. The processing unit 8 may comprise a communication interface to allow communication with an external device. The interface may be wired and/or wireless. This may allow upload and/or synchronisation of data to a remote device. For example, the user may upload data to a cloud server or the like.

The processing unit 8 may comprise a suitable controller (e.g. comprising at least one processor and at least one memory circuit, a system-on-chip (SoC), an application-specific integrated circuit (ASIC) or another technical equivalent) to to provide processing the received measurements. The processing unit 8 may comprise memory to store some or all of the data received thereby. It can be appreciated the exact form of the processing unit 8 is not pertinent to the invention at hand. In some embodiments, the processing unit may be provided by a conventional computing device, for example, a mobile phone. The computing device may comprise software configured to interrogate the exercise device 2 and/or to receive data therefrom. For example, an app may be provided on the mobile device.

The inventors have found that the oxygen consumption or equivalently oxygen uptake (i.e. the volume of oxygen consumed per unit time, shortly "V02" in the literature) during rest period after phosphagen regime based physical activity provides an improved indicator of ATP regeneration. Thus, the oxygen consumption can be used to determine the optimum period of rest between periods of a phosphagen consuming activity during an exercise. The oxygen consumption, 1702, can be determined using the Fick Equation: Vo2 = co(cc, -c) Where CO is the cardiac output, and Ca -C" is the difference of oxygen 30 content between arterial blood and venous blood, (often referred to arteriovenous oxygen difference in the literature).

Given that cardiac output is determined by a product of a stroke volume and a heart rate (stroke volume x heart rate), and Ca -C" is approximately constant during physical activity of a certain limited duration, e.g. a single physical exercise, the oxygen consumption can be determined as a function of the stroke volume and heart rate. The device 2 may therefore receive stroke volume and heart data measured by the electrodes and determine an oxygen consumption accordingly.

Ca -Ci, may be derived from known data (i.e. provides a fixed value). The value may be provided using blood tests and/or measuring inhaled/exhaled gases in a closed system when the cardiac output is measured simultaneously. The data may be modified according to one or more characteristic of the user. For example, the user may input one or more of: height; weight; age; sex; fitness level; or other physiological characteristics that influences Ca -C,,. The system is configured to determine the appropriate Ca -C., according to said characteristics. For example, the appropriate Ca -C" may be retrieved from a database, determined by an algorithm or heuristic, or derived using multivariate regression etc. In other embodiments, the Ca -Ci, may be measured using known techniques to provide an empirically derived value.

Ca -Ci, may vary in accordance with the user's fitness level (e.g. may increase with improving fitness level). As a consequence, the user may wish to calibrate Ca -Ci, over a period of time. For example, the user may measure and recalibrate Ca -C" every few months, or with general improvement of their fitness. The calibration may be made according to the above-described principles, e.g. by using the Fick principle and measuring the V02 and the cardiac output and computing the Ca -C" as their ratio according to the Equation above. The calibration may be performed occasionally, e.g. weekly or monthly, daily, between consecutive exercises, or even within a single exercise between activity periods after the user is ready to start the next activity period and before starting the next activity period. Once the appropriate Ca -C" value is determined/measured, the value is stored on the device for the particular user. It also has been observed that Ca -C., evolves during a given physical activity, however, there is little change in the early stages of a physical activity. In the case of phosphagen regime activities, Ca -C can thus be considered to be constant.

A schematic for oxygen consumption as a function of time for a period of activity and subsequent rest period is shown in figure 3. A relative indication of physical activity is shown by the solid line 16. The rectangular shape of the physical activity represents a short burst of high-intensity physical activity. The physical activity typically comprises maximum effort or maximum exertion, e.g. a running sprint with maximum speed (optionally with weights) or weightlifting with maximum strength. It can be appreciated that a particular exercise comprises one or more of such periods of physical activity.

During the period of activity 18, the oxygen consumption 20A increases rapidly. The oxygen consumption 20A typically does not reach steady state due to the shod period of phosphagen regime activity. Typically, the period of activity 18 is less than or equal to 30 seconds; preferably, less than or equal to 20 seconds; preferably, less than or equal to 15 seconds; preferably, less than or equal to 10 seconds. The period of activity may be between 1 and 15 seconds; preferably between 1 and 10 seconds; preferably between Sand 10 seconds (including the end points in each range). The activity will typically be intense and short-termed (i.e. such that only/predominantly ATP depletion occurs). The activity may be a maximum sprint or a weight exercise, as described above.

A rest period 22 is provided after the activity period 18. During the rest period, the oxygen consumption decreases as the body recovers. During rest, the oxygen consumption is provided as two components 22B and 22C. The first component 22B provides regeneration of the ATP. The first component 22B thus diminishes relatively rapidly (e.g. within 1-5 minutes). The second component 22C relates to regeneration from glycolytic process. This process is both lower in magnitude of oxygen consumption and diminishes at a lower rate (i.e. the gradient is less than that of the first component 22B). It can therefore be seen that the oxygen consumption decreases relatively rapidly during the ATP regeneration phase. As such, both the magnitude of oxygen consumption and/or the rate of change (i.e. differential) thereof are indicative that ATP regeneration is complete. The inventor has found that the oxygen consumption provides a relatively accurate indicator of the desired rest period for ATP regeneration accordingly. It should be appreciated that the oxygen consumption curve 20A is a simplified and generalized illustration. In reality, the oxygen consumption curve may take a different form in a phosphagen regime exercise. For example, the oxygen consumption may keep rising for a while after the activity period 18 has ended, before starting the decline illustrated in Figure 3. Furthermore, personal characteristics and the type of activity may affect the oxygen consumption curve. In any case, the embodiments described herein apply to such variations of the oxygen consumption because the embodiments monitor the decline of the oxygen consumption.

An example of such an analysis is shown in figure 4. In a first example, the end of ATP regeneration phase is determined by a threshold absolute value of the oxygen consumption 1702(a). The time at which the measure 1O2 reaches this value is provided at t(a), and the total time rest time period is 22A. The value of the threshold fl02 may be, for example, about one litre per minute (L/min). For example, the threshold may be selected from a range of 0.5 to 1.5 L/min; preferably, 0.8 to 1.2L/m; preferably, 0.8 to 1Um. The threshold VO2 may be fixed across all users (i.e. such that it is not personalized to the user). Alternatively, it may be fixed for the particular user (but vary between different users).

In a second example, the rate of change of the oxygen consumption, 1702 is shown in the dashed line 24. The rate of change of the oxygen consumption is determined by the gradient or a differential of the measured oxygen consumption. The gradient may be determined in near real time from the oxygen consumption data using known algorithms. The modulus of the gradient is shown for ease of explanation in figure 4, however, it can be appreciated the 902 curve may comprise a more complex form (i.e. it need not be a straight line as shown in figure 4). The end of ATP regeneration phase is determined by a threshold value of the oxygen consumption rate of change 02(b). The time at which the measure Po2 reaches this value is provided at t(b), and the total time rest time period is 22B.

Referring to figure 5, in some embodiments, the oxygen consumption threshold may be determined as a function of the maximum oxygen consumption, 02(max). The threshold may be a fraction or percentage of the maximum oxygen consumption. For example, the threshold may be less than or equal to 30%; 25%; 20%; or 15% of the maximum oxygen consumption. The maximum oxygen consumption may have been measured during earlier activity. In other words, it may be a predefined parameter that may have been measured and/or approximated based on one or more of the user's personal characteristics, for example, a ratio between a maximum heart rate and a resting heart rate. There exists several fitness tests and formulas for calculating an approximation of the maximum oxygen consumption. The threshold can therefore be calculated accordingly.

In some embodiments, the oxygen consumption threshold may be determined as a function of the resting oxygen consumption, 1.7 02(rest). The resting oxygen consumption may be determined when the user is at rest during the exercise, i.e. during a rest period. The resting oxygen consumption could be the lowest oxygen consumption level measured during the rest period, e.g. the oxygen consumption value at the end of the rest period. The threshold may be a multiple or percentage of the resting oxygen consumption. For example, the threshold may be less than or equal to 300%, 200%, or 150% of the resting oxygen consumption. Measurements of resting oxygen consumption may be performed before the activity to establish a baseline for at least the first rest period. In the subsequent rest periods, the same (predetermined) resting oxygen consumption may be used, or a new resting oxygen consumption value may be measured during each rest period. The device 2 may prompt the user to record a new baseline resting oxygen consumption during a period of rest and/or before initiation of the next period of activity. Additionally or alternatively, the resting oxygen consumption may be input from the user (e.g. from measurement elsewhere).

In some embodiments, the threshold can be determined by analyzing a characteristic shape of the oxygen consumption curve. In some embodiments, higher order polynomial or exponent correlations in the oxygen consumption may be used. In some embodiments, pattern recognition may be used on the oxygen consumption data to determine a point characteristic of partial or complete ATP regeneration.

It can be appreciated that determination of the end of the rest period and/or regeneration of ATP can be provided by any of the above metrics, alone or in combination with one another. In specific embodiments, determination of the end of the rest period may be provided by either or both of the oxygen consumption and the differential thereof. For example, an absolute oxygen consumption threshold value and a differential threshold value may be predefined. The end of the rest period may be determined if either of the absolute value or differential value is reached (i.e. regardless of the state of the other). In some examples, both the absolute value and differential value must be reached before the end of the rest period is determined.

The oxygen consumption threshold may be variable in accordance with one or 30 more physiological characteristic of the user. This provides a tailored experience for the user. For example, the threshold may vary with: the weight; height; age; sex; general fitness level; lung capacity; peak flow rate; and/or resting/average heat rate of the user, or any combination of one or more of these variables. The user may input one or more of the variables and/or the variables may be measured using the device accordingly. The user may complete a questionnaire, profile or like to provide said variable(s). The appropriate threshold value may be retrieved from an internal/external database in accordance with said variables and/or determined algorithmically.

In some embodiments, the oxygen consumption threshold is a fixed (i.e. across all devices, and users). This may be beneficial where the variation in the oxygen consumption threshold is negligible across users or select group of users.

In some embodiments, the oxygen consumption threshold may be variable in accordance with one or more environmental condition for the user, for example: temperature; humidity; oxygen concentration (e.g. as a function of altitude); time of day; and/or time of year. The device may comprise one or more sensors to measure said environmental condition (e.g. thermometer, altimeter, clock etc.) and/or may be operatively connected to such sensor.

The threshold can therefore be modified to provide a custom value for the user, thus ensuring greater accuracy. Nevertheless, in some cases the oxygen consumption threshold may be approximately independent of physiological/environmental variables, particularly when the threshold is derived by the characteristic shape of the oxygen consumption curve (e.g. the differential, f/02(rest) multiple or t702(max) fraction). The present arrangement may therefore be substantially user independent.

It can be appreciated that the threshold value indicative of the end of the rest period is arbitrary, and such a value may be varied according to user needs.

The end of the rest period may be determined before, after, or at the point where the first component 22B of the oxygen consumption is determined to have diminished (i.e. when ATE' regeneration is complete). For example, for endurance training, only partial ATP regeneration may be beneficial, thus the threshold for the oxygen consumption value may be defined at a point where only partial ATP regeneration has occurred, and the oxygen consumption has only partially decreased accordingly. For hypertrophy, the threshold for the oxygen consumption value may also be defined at a point where only partial ATP regeneration has occurred. As such, the threshold may define a lower oxygen consumption value than the threshold for the endurance. Conversely, for strength training, complete ATP regeneration may be required, and so the threshold for the oxygen consumption value is defined at an even lower point where complete ATP regeneration has occurred, and the oxygen consumption diminished accordingly. The user may therefore select a desired exercise/activity type or training benefit (e.g. endurance, hypertrophy, or strength), and the threshold may be determined accordingly.

The user may be able to directly vary oxygen consumption threshold in accordance with their desired exercise regime and/or training benefit. For example, the user may be able to manually input specific values. Additionally or alternatively, the user may be able to manually input values on an arbitrary scale (e.g. "HIGH", "MEDIUM", "LOW' etc.).

Schematic operation of the device is shown in figure 6. The user places the electrodes 4 on their chest, or an equivalent measurement system for measuring the oxygen consumption, and may place the processing unit on their wrist or operatively connect the electrodes 4 with their mobile device, as required. In a first step 26, the exercise phase is initiated. In the next step 28, the user performed a series of activity and rest period(s) in accordance with a selected (phosphagen regime) exercise type and the determined rest period(s). In a final step 30, the exercise (i.e. session or routine) is ended.

The process is described in further detail with reference to figure 7. In step 32, the user may select an exercise or activity type. An example of the activity type selected for embodiments described herein may be a strength exercise or a maximum running sprint exercise that represent the phosphagen regime activity types. Other activity types available for selection may include a running exercise, a cycling exercise, and a swimming exercise. Each activity type may further have a sub-type such as a long-distance low-intensity running exercise, an interval running exercise, and a medium-distance steady intensity running exercise. Similar sub-type classification may be provided for other activity types. This is typically performed before beginning any physical activity to ensure the device is properly configured. The device 2 may then determine appropriate exercise training guidance and select appropriate measurement metric(s). The system may also select and configure length, intensity and/or number of physical activity periods and/or rest periods for the given exercise. The length/intensity may be provided to the user by the display 12. The user may be able to select/input the desired exercise or modify the exercise via the device and/or via a connected remote device. The device comprises a plurality of preprogrammed exercise types. The appropriate measurement metrics may include, for example, heart rate, speed, and cadence for a steady-intensity exercise while the stroke volume may be used (additionally or alternatively) as a measurement metric for an interval exercise, e.g. for determining an end of a rest period as described in WO'599.

In the next step 34, the appropriate sensor functions required for measuring the selected type of exercise are determined. Where a user selects a phosphagen type exercise, such as the strength exercise or maximum sprint exercise, the system will use the above oxygen consumption parameter to determine the rest period, e.g. the end of the rest period, and use the corresponding sensor functions. If the user selects a glycolysis regime exercise or another non phosphagen regime exercise, then rest period may be determined on the basis of the heart rate or stroke volume or timer, as is known, and use corresponding sensor functions. In the present embodiment, the sensors may include a heart rate sensor, bioimpedance and/or electrocardiogram (ECG) as described above.

In the next step 36, the exercise is initiated or triggered. The device 2 may provide a notification to the user to start the exercise. The notification may be audible/visual/tactile.

In step 38, the user may perform a warm up activity or exercise. It can be appreciated that such a step is optional, and the length/intensity/type of activity for the warm up will be determined in accordance with the selected exercise. The user may provide an indication to the device warm up is complete and/or the device may determine said warm up is complete automatically (e.g. where the warm up is a fixed length or until a predetermined heart rate is achieved).

In step 28, the activity and subsequent rest periods are performed. The process is described with reference to figure 8.

In step 40, the device determines physical activity is initiated. Typically, this is manually initiated by the user (for example, using the manual input). In some embodiments, the device is configured to automatically detect when activity is initiated. For example, the device may monitor one or more of: heart rate; oxygen consumption; and/or movement (e.g. via inertial sensors). If one or more variable reaches a threshold indicating initiation of activity, e.g. a motion sensor detects motion above a threshold, then the start of the activity is determined accordingly.

In the next step 42, the end of the activity period 18 is determined. This may be determined in substantially the same way as initiation of the activity (e.g. manually and/or automatically). In some embodiments, determination of the end of activity period is provided by a measured parameter, such as reduction or stop of motion or a timer counting the activity period expiring.

In some embodiments, the end of the activity period may be determined in accordance with the selected exercise or exercise type. If the selected exercise comprises activity periods of a predetermined length, then the end of the activity period is provided by the predetermined length from initiation of the start of the activity period. For example, if the activity period is defined to be 5 or 10 seconds long, then end of the activity period is simply determined as 5 or 10 seconds from the start of the activity period, respectively. The device 2 may 5 provide a notification to the user to end the activity period. The end point of the activity period is therefore fixed. In some embodiments, the user may manually indicate that activity period is complete. These embodiments may be specific to the phosphagen regime activity. In a case of another activity type, the end of the activity period may be based on the sensor functions, e.g. on the measured 10 stroke volume and/or heart rate.

In the next step 44, the beginning of the rest period 22 is determined. Typically, this will be synchronous with the end of the activity period 18, and thus determination of the beginning of the rest period 22 follows directly the 15 determination of the end of the activity period 18.

In the next step 46, the measured oxygen consumption is monitored during the rest period 22. The oxygen consumption monitoring may be initiated at this stage, or may be continually being performed (e.g. also during the activity phase). The oxygen consumption may be determined as described in WO'599, or according to another state-of-the-ad measurement technique. In the context of sports, it would be preferable if the measurement system would be portable or even wearable. Following WO'599, the heart stroke volume and heart rate are measured via the electrodes 4. In some embodiments, the heart rate is measured with a different technology, for example, using photoplethysmography measured from the user's wrist. The measurements are then processed by the processing unit 8 to determine the oxygen consumption, as described above.

The stroke volume and the heart rate measurements may be combined in a synchronized manner to provide the cardiac output parameter that directly indicates the oxygen consumption, with the arteriovenous oxygen difference being constant during the phosphagen regime physical activity. It should be appreciated that the exact computation may vary. For example, the processing unit 8 may compute the oxygen consumption as a product of the constant arteriovenous oxygen difference and the cardiac output and compare the oxygen difference with the threshold. Another alternative embodiment is to compute the cardiac output, scale the threshold on the basis of the arteriovenous oxygen difference and compare the cardiac output with the scaled threshold. In both cases, the processing unit effectively monitors the oxygen consumption with respect to the threshold according to the above-described principles. Oxygen consumption is monitored continuously and/or performed at relatively small time intervals (e.g. 1 second or less). The oxygen consumption may be displayed to the user in real-time (e.g. via the display or connected device).

In the next step 48, the measured oxygen consumption is compared to the threshold consumption value. It can be appreciated the monitoring 32 and comparison 34 step are typically performed concurrently. In some embodiments, the comparison step 34 may be performed after a predetermined time period to avoid unnecessary computation (e.g. to save battery power). For example, it may be determined that the rest period shall always be at least x seconds, where x may be 10, 20, 30, or 60 seconds. After the x seconds has expired, the oxygen consumption measurements and analysis may be triggered.

The measured oxygen consumption threshold or parameter may be variable in accordance with the selected exercise provided in step 32. The measured oxygen consumption threshold/parameter is therefore compared against said selected oxygen consumption threshold/parameter in step 48 accordingly. The threshold/parameter may therefore be modified between exercises of a different type.

If the measured oxygen consumption meets a predetermined parameter, then the system is configured to provide an indication that said parameter is met. In the present embodiment, a notification 50 is provided to the user. For example, if the absolute value of the oxygen consumption falls below the threshold value, then a notification is generated. If the rate of change (differential) of the measured oxygen consumption is monitored, the notification may be generated when the rate of change drops below a threshold. Since the differential is negative due to the oxygen consumption decreasing during the rest period, the notification may be output when the differential rises above a threshold. The notification typically informs the user that the user has recovered from the previous activity period and is ready to start the next activity period. In other words, the notification may inform that the rest period is at an end (i.e. ATP regeneration is complete). The user may therefore resume their exercise routine (i.e. begin the next physical activity in the routine) by manually triggering the start of the next activity period.

The notification may take any suitable form. The notification may be audible (e.g. an alarm), visual (e.g. a flashing LED), and/or tactile (e.g. vibration). The notification may be provided on the display 12. The notification may provide instructions for the user. For example, the notification may state "END REST" or "RESUME ACTIVITY".

In some embodiments, notification may be provided before the end point of the rest period 22. This may allow the user to prepare for the activity before the end point of the rest period 22. The system may therefore estimate the end point of the rest period 22 and notify the user at a predetermined before said end point. For example, the system may notify the user 10 or 20 seconds before the determined end point. A common method is a countdown timer counting from five to zero seconds. The countdown may be indicated via sound, display, and/or vibration outputs.

If the measured oxygen consumption does not meet the predetermined parameter (i.e. threshold), then the system continues the monitoring 32 and comparison 34 steps. The device may provide a notification to the user to continue resting, for example "CONTINUE REST". This step is repeated until the parameter is met. A timer may determine the maximum length of the rest period 22. This may be recorded for later retrieval and/or used in further analysis. If the parameter is not met within a predetermined time period corresponding to the maximum length, then a notification may be provided to the user that the rest period is at end and the user has recovered sufficiently for the next activity period (e.g. a timeout message). The predetermined timeout period is time greater than typical maximum time needed for the ATP regeneration, for example, at least 5 minutes or at least 10 minutes or at least 15 minutes. In the embodiment where the threshold is set by the desired training benefit, the timeout period may be adapted accordingly. The timeout period may be 40 seconds for the endurance training benefit, 100 seconds for the hypertrophy training benefit, 5 minutes for the strength training benefit, and 15 minutes for a sprint running exercise.

In case the activity type is another than the phosphagen regime activity type, the device may utilize other sensor functions to determine the user's readiness for the next activity period. For example, if the activity type is an interval running exercise where the work periods are longer than in the phosphagen regime exercises, e.g. at least one minute, the device may measure the heart activity (e.g. heart rate or stroke volume) during the rest period and determine whether the heart activity measured during the rest period meets a predetermined heart activity threshold, e.g. a stroke volume threshold or a heart rate threshold. If the heart activity threshold is met, the notification of the readiness for the next work period may be output. Otherwise, the indication of the continuing rest period may be output.

In some embodiments, determination of the measured oxygen consumption meeting predetermined parameter may not be provided directly to the user. For example, said determination may merely be recorded on the device. This may allow the user to compare the measured ideal rest period against their actual rest period at a later time. In other embodiments, a notification could be provided to a remote device, such as a trainer's device. The trainer could then manually instruct the user as required.

The process may be repeated for any number of sequential activity and rest periods accordingly. The number of repetitions will be determined according to the selected exercise type, the user's training plan, the user's fitness level, the user's recovery state, or any combination of two or more of these factors. Typically, each rest period is less than or equal to 15 minutes; preferably, less than equal to 10 minutes; preferably, less than or equal to 7 minutes; preferably, less than or equal to 5 minutes. In some embodiments, each rest period is less than or equal to 3 minutes; preferably, less than or equal to 2 minutes. Termination of the exercise routine may be initiated manually, or after a predetermined number of repetitions of the sequence of activity and rest periods according to the training plan.

Referring back to figure 6, once the desired number of activity/rest period iterations is complete, a cooldown period may be initiated. Again, the length/intensity/type of activity for the warm up may be determined in accordance with the selected exercise and/or physical parameters of the user (e.g. heart rate).

In a final step 54, the exercise is completed. The user may download or extract any data from the device as required, e.g. a summary of the exercise. The data may be stored in the device or in a cloud storage in the user's user account to allow tracking of user performance over time.

In some embodiments, the ventilation of the user is determined. The ventilation may be determined as described in WO'599. In short, ventilation is the volume of gas entering the lungs per unit time. This is derived from multiplying the tidal volume by the respiratory rate (breathing frequency). The tidal volume and the ventilation may be measured by measuring transthoracic bioimpedance of the user. In practice, at least partially the same electrodes used for measuring the stroke volume may be used for measuring the tidal volume and the ventilation. 5 There exist methods where the measured transthoracic impedance is mapped directly to the ventilation. Other solutions measure the tidal volume via bioimpedance and the respiratory rate from the electrocardiogram separately and compute the ventilation as their product. In yet another solution, the tidal volume is approximated as constant and the ventilation is estimated from the 10 measured respiratory rate without the need to measure the tidal volume. Further methods also exist.

Generally, increased ventilation is an indicator of increased need for oxygen to replenish the energy reserves. In the context of the phosphagen regime activity of 10 seconds or less, only the ATP resources have been depleted. As a consequence, the increased oxygen requirement is related to the replenishment of the ATP reserves and is thus as an indicator equivalent to the oxygen consumption for the above-described purposes. The ventilation may be used as an alternative to the oxygen consumption to measure the user's state of recovery and to end the rest period. In another embodiment, the measured ventilation is used to improve the recovery estimation in connection with the oxygen uptake measurements. The system may monitor the ventilation and determine if the ventilation meets more or more predetermined parameter. Typically, the parameter comprises a threshold ventilation value. For example, the system determines if the measured ventilation is below the threshold. If the measured ventilation is below said threshold ventilation value, then an end of the rest period may be determined. Thus, the ventilation may be used to determine the extent of ATP regeneration. The threshold ventilation value may be based on the user's ventilation at rest, measured or otherwise given as an input. In other embodiments, the differential, integral, maximum fraction or at-rest multiple may be used as described in relation to the heart activity/oxygen consumption value derivation.

In the present embodiment, the ventilation is used in combination with the oxygen consumption measurements. For example, the rest period may be determined as complete when either the oxygen consumption threshold or the ventilation threshold is met. The user is therefore notified when either the oxygen consumption or the ventilation threshold is met accordingly. In other examples, the rest period may be determined as complete when both the ventilation and oxygen consumption threshold is met. Thus, upon determination of one of the ventilation and oxygen consumption threshold is met, notification of the end of rest period is delayed until determination of the other of ventilation and oxygen consumption threshold is met.

In some embodiments, the ventilation may be used without the oxygen consumption measurements when determining the end of the rest period. 15 Thus, determination of the rest period is provided by the ventilation measurements and the associated threshold alone.

The present system provides an improved means of estimating the ATP regeneration during a rest period following phosphagen type activity. The system mitigates the need for invasive or restrictive tests, for example, using closed cycle mask tests. The system may therefore be used in a wide variety of environments without the needs for specialist training or equipment. The system may be tailored to an individual's needs.

The present system allows for selection of a specific exercise type, thus providing selection of specific rest period accordingly. This allows the user to select a desired outcome for their exercise routine (e.g. endurance, or muscle mass etc.). The system may use multiple variable (e.g. heart activity and ventilation), thus providing more accurate determination of the rest period.

It can be appreciated that scales, shapes or forms of the graphs shown in figure are arbitrary, and are merely constructed to aid with understanding of the invention.

Claims

Claims: 1. A method of determining a desired rest period for a phosphagen regime physical activity of a user, comprising: determining an end of the physical activity and the start of a rest period of the user; measuring an oxygen consumption during the rest period; determining whether said oxygen consumption meets one or more predetermined parameter; and providing an indication if the one or more parameter is met.
2. A method according to claim 1, comprising providing a notification to the user if the parameter is met.
3. A method according to claim 1 or 2, wherein said measuring the oxygen consumption comprises measuring heart activity of the user during the rest period, the heart activity comprising a heart stroke volume and a heart rate of the user and determining the oxygen consumption based on said measured heart stroke volume and heart rate.
4. A method according to any preceding claim, where the predetermined parameter comprises an absolute value of oxygen consumption.
5. A method according to any preceding claim, where the predetermined parameter comprises a rate of change/differential of oxygen consumption.
6. A method according to any preceding claim, comprising providing a resting oxygen consumption, and where the predetermined parameter comprises a ratio of oxygen consumption and the resting oxygen consumption.
7. A method according to any preceding claim, where the predetermined parameter comprises a threshold oxygen consumption and comprising determining whether the measured value of oxygen consumption is above or below said threshold, and performing a first action if the measured value of oxygen uptake is above said threshold, and a second action if the measured value of oxygen uptake is below said threshold.
8. A method according to claim 6, where one of the first and second action is to indicate to a user to maintain the rest period and/or the other of the first and second action is an indication to the user of readiness to start a next activity period.
9. A method according to any preceding claim, where the notification comprises an audible, visual and/or tactile notification.
10. A method according to any preceding claim, comprising providing a selection of an activity type, and the oxygen consumption parameter is variable in accordance with said activity type.
11. A method according to any preceding claim, comprising providing a selection of an activity type, and if the activity type is a first activity type, performing said determination whether said oxygen consumption meets said one or more predetermined parameter and providing the indication, if the parameter is met; if the activity type is a second activity type, determining whether heart activity measured during the rest period meets a predetermined heart activity threshold, and providing the indication, if the heart activity threshold is met.
12. A method according to any preceding claim, where the oxygen consumption parameter is variable in accordance with one or more predetermined physiological variable of the user.
13. A method according to any preceding claim, comprising measuring ventilation of the user and determining whether said ventilation meets one or more predetermined parameter.
14. A method according to claim 13, comprising providing a notification to the user if the ventilation parameter is met, the notification comprising an indication to the user to maintain a rest period and/or to end a rest period.
15. A method according to claim 13 or 14, comprising providing a notification to user when either the oxygen uptake value parameter or ventilation parameter is met.
16. A method according to any of claims 13-15, comprising providing a notification to user when both the oxygen uptake value parameter and ventilation parameter are met.
17. A method according to any preceding claim, where the period of activity is less than or equal to 15 seconds.
18. A method according to any preceding claim, where timer the rest period is less than or equal to 15 minutes.
19. A computer program or computer readable medium comprising program instructions which, when executed by the computer, cause the computer to carry out a computer process implementing the method according to any preceding claim.
20. A device configured to determine a desired rest period for a phosphagen regime physical activity of a user, and comprising a controller configured to: determine an end of the physical activity and the start of a rest period of the user; receive measurements of the oxygen consumption during the rest period; determine whether said oxygen consumption meets one or more predetermined parameter; and where the device is configured to provide an indication if the one or 30 more parameter is met.
21. The device according to claim 20, operatively connected to a plurality of electrodes to provide said heart activity measurements.
22. A wearable device comprising the device according to claims 20 or 21
23. A wearable device according to claim 22, where the wearable device is wrist or arm device.
24. A method of determining a desired rest period for a phosphagen regime physical activity of a user, comprising: determining an end of the physical activity and the start of a rest period of the user; measuring ventilation of the user during the rest period; determining whether said measured ventilation meets one or more predetermined parameter; and comprising providing an indication if the parameter is met.
25. The method according to claim 24, wherein the ventilation is measured as a combination a measured breathing rate and tidal volume of the user.