Concurrent heart rate validity of wearable technology devices during trail running.

Validation of heart rate responses in wearable technology devices is generally composed of laboratory-based protocols that are steady state in nature and as a result, high accuracy measures are returned. However, there is a need to understand device validity in applied settings that include varied intensities of exercise. The purpose was to determine concurrent heart rate validity during trail running. Twenty-one healthy participants volunteered (female n = 10, [mean (SD)]: age = 31 [11] years, height = 173.0 [7] cm, mass = 75.6 [13] kg). Participants were outfitted with wearable technology devices (Garmin Fenix 5 wristwatch, Jabra Elite Sport earbuds, Motiv ring, Scosche Rhythm+ forearm band, Suunto Spartan Sport watch with accompanying chest strap) and completed a self-paced 3.22 km trail run while concurrently wearing a criterion heart rate strap (Polar H7 heart rate monitor). The trail runs were out-and-back with the first 1.61 km in an uphill direction, and the 1.61 return being downhill in nature. Validity was determined through three methods: Mean Absolute Percent Error (MAPE), Bland-Altman Limits of Agreement (LOA), and Lin's Concordance Coefficient (rC). Validity measures overall are as follows: Garmin Fenix 5 (MAPE = 13%, LOA = -32 to 162, rC = 0.32), Jabra Elite Sport (MAPE = 23%, LOA = -464 to 503, rC = 0.38), Motiv ring (MAPE = 16%, LOA = -52 to 96, rC = 0.29), Scosche Rhythm+ (MAPE = 6%, LOA = -114 to 120, rC = 0.79), Suunto Spartan Sport (MAPE = 2%, LOA = -62 to 61, rC = 0.96). All photoplethysmography-based (PPG) devices displayed poor heart rate agreement during variable intensity trail running. Until technological advances occur in PPG-based devices allowing for acceptable agreement, heart rate in outdoor environments should be obtained using an ECG-based chest strap that can be connected to a wristwatch or other comparable receiver.

Step Count Reliability and Validity of Five Wearable Technology Devices While Walking and Jogging in both a Free Motion Setting and on a Treadmill.

Wearable technology devices are used by millions of people who use daily step counts to promote healthy lifestyles. However, the accuracy of many of these devices has not been determined. The purpose was to determine reliability and validity of the Samsung Gear 2, FitBit Surge, Polar A360, Garmin Vivosmart HR+, and the Leaf Health Tracker when walking and jogging in free motion and treadmill conditions. Forty volunteers completed walking and jogging free motion and treadmill protocols of 5-minute intervals. The devices were worn simultaneously in randomized configurations. The mean of two manual steps counters was used as the criterion measure. Test-retest reliability was determined via Intraclass Correlation Coefficient (ICC). Validity was determined via a combination of Pearson's Correlation Coefficient, mean absolute percent error (MAPE: free motion ≤ 10.0%, treadmill ≤ 5.00%), and Bland-Altman analysis (device bias and limits of agreement). Significance was set at p < 0.05. The Samsung Gear 2 was deemed to be both reliable and valid for the jogging conditions, but not walking. The Fitbit Surge was reliable and valid for all conditions except for treadmill walking (deemed reliable, ICC = 0.76; but not valid). The Polar A360 was found to be reliable for one condition (treadmill jog ICC = 0.78), but not valid for any condition. The Garmin Vivosmart HR+ and Leaf Health Tracker were found to be both reliable and valid for all situations. While each device returned some level of consistency and accuracy during either free motion or treadmill exercises, the Garmin Vivosmart HR+ and the Leaf Health Tracker were deemed to be reliable and valid for all conditions tested.

Reliability of Trail Walking and Running Tasks Using the Stryd Power Meter.

Footpod monitors are wearable devices attaching to the shoe with the ability to sense oscillations in leg movement; however, few studies provide reliability. The purpose was to provide reliability data for outdoor tasks as measured by the Stryd Power Meter, which is a footpod monitor. Young healthy individuals (N=20, male n=12, female n=8) completed two 5-min self-paced walks along a trail, and two 5-min trail runs. Reliability of the tasks was determined using Coefficient of Variation (CV), Intraclass Correlation (ICC), and 95% confidence intervals (CI). Measures during trail running that returned a CV less than 10%, met the ICC threshold of 0.70, and displayed good to excellent 95% CI included pace, average elapsed power, average elapsed form power, average elapsed leg spring, and vertical oscillation. The only variable during walking to meet these criteria was maximal power (CV=4.02%, ICC=0.968, CI=0.902, 0.989). Running tasks completed on a trail generally return more consistent measures for variables that can be obtained from the Stryd footpod device than walking tasks.

Reliability of the Polar T31 Uncoded Heart Rate Monitor in Free Motion and Treadmill Activities.

The Polar T31 uncoded heart rate monitor (T31) is currently accepted as a precision measurement device that can be used in lieu of electrocardiography. However, minimal literature exists to verify reliability when used for this purpose. The purpose of this study is to evaluate the reliability of heart rate (HR) measurements obtained from the T31. Forty volunteers participated in a three-day test-retest protocol. Participants gave anthropometric data on the first day. On the second day, they performed two 5-minute self-paced free motion walks (FMW) and two 5-minute self-paced free motion jogs (FMJ). Finally, on the third day, they performed two 5-minute treadmill walks (TW) and two 5-minute treadmill jogs (TJ). Treadmill speeds for each TW and TJ were determined by the distances traveled during the FMWs and FMJs on day 2. HR values at rest (HRR) and while in motion (minutes 1-5) were evaluated (HRM). Values calculated used Cronbach's α (≥0.70) for reliability with significance accepted at p<0.05. FMW HRR (all, α=0.96; male, α=0.97; female, α=0.94), FMJ HRR (all, α=0.98; male, α=0.98; female, α=0.99), TW HRR (all, α=0.96; male; α=0.92; female, α=0.98), TJ HRR (all, α=0.97; male, α=0.98; female, α=0.96), FMW HRM (all, α=0.93; male, α=0.93; female, α=0.91), FMJ HRM (all, α=0.93; male, α=0.94; female, α=0.90), TW HRM (all, α=0.95; male, α=0.92; female, α=0.95), TJ HRM (all, α=0.94; male, α=0.95; female, α=0.92). All p-values < 0.001. The T31 provided reliable measures at rest and for walking and jogging in both a free motion and treadmill setting.

Reliability and Validation of the Hexoskin Wearable Bio-Collection Device During Walking Conditions.

To evaluate if the Hexoskin smart shirt (HxS) would produce valid and reliable measurements for heart rate (HR), respiratory rate (RR), minute ventilation (VE), step count (SC), and energy expenditure (EE) when compared to a Polar T-31 heart rate monitor, an Applied Electrochemistry Moxus Metabolic System, and a manual step count. A two-day walking treadmill protocol with participants walking for 3 minutes at 3 speeds (1.5mph, 2.5mph, 3.5mph, 0% grade) was performed. Forty-nine volunteers participated the first day, forty-six on the second, thirty-one were used for reliability. Values calculated for the HxS data used Pearson's product-moment correlation (p < 0.05; r ≥ 0.70) for validity and Cronbach's α (≥ 0.70) for reliability. HxS HR (1.5mph; p<0.01, r=0.86, α=0.86. 2.5mph; p<0.01, r=0.81, α=0.88. 3.5mph; p<0.01, r=0.85, α=0.85), HxS RR (1.5mph; p<0.01, r=0.87, α=0.93. 2.5mph; p<0.01, r=0.86, α=0.92. 3.5mph; p<0.01, r=0.71, α=0.76), HxS VE (1.5mph; p=0.66, r=0.11, α=0.70. 2.5mph; p=0.01, r=0.15, α=0.73. 3.5mph; p=0.31, r=0.08, α=0.14), HxS SC (1.5mph; p=0.90, r=-0.01, α=0.70. 2.5mph; p=0.22, r=0.13, α=0.86. 3.5mph; p<0.01, r=0.74, α=0.85), HxS EE (1.5mph; p<0.01, r=0.56, α=0.85. 2.5mph; p<0.01, r=0.50, α=0.83. 3.5mph; p<0.01, r=0.51, α=0.80). HxS HR and RR provided valid and reliable measures at all three speeds while VE, SC, and EE had a mixture of results based on speed. These results are important in the use of the Hexoskin in an accurate manner for athletes, coaches, and for the potential medical applications being advocated in the field of telemedicine procedures.

Sex and Age Differences in Trail Half Marathon Running.

Female participation is growing in trail running races. The purpose was to evaluate sex and age differences in top finishers of a trail running half marathon. Velocity differences between males (M) and females (F) were determined for the top 10 finishers of the Moab Trail Half Marathon from 2012 - 2015 across age, and by finishing place. Differences between age category and between sexes were determined through ANOVA with significance accepted at P < 0.05. A significant difference for running velocity was present between sexes at each age category (20-29 yr F = 2.9±0.3, M = 3.4±0.4 m·sec-1; 30-39 yr F = 2.8±0.3, M = 3.3±0.3; 40-49 yr F = 2.7±0.3, M = 3.0±0.5; 50-59 yr F = 2.3±0.2, M = 2.8±0.3; 60-69 yr F = 1.6±0.3, M = 2.2±0.4; P < 0.0001). Sex difference in trail running velocity was consistent (~13%) among all age categories with exception of the oldest group (33%, P = 0.0001). There were significantly greater female finishers in every age category (20 - 29 yr F = 107±18, M = 56±1;, 30 - 39 yr F = 150±34, M = 84±21; 40 - 49 yr F = 112±17, M = 64±16; P < 0.01) until 50 - 59 yr (F = 48±13, M = 41±14; P = 0.50). These data indicate that the widening gap in sex differences observed in road races are ameliorated in a trail running environment that has a larger number of female participants.