Aerobic capacity, activity levels and daily energy expenditure in male and female adolescents of the kenyan nandi sub-group

The relative importance of genetic and socio-cultural influences contributing to the success of east Africans in endurance athletics remains unknown in part because the pre-training phenotype of this population remains incompletely assessed. Here cardiopulmonary fitness, physical activity levels, distance travelled to school and daily energy expenditure in 15 habitually active male (13.9±1.6 years) and 15 habitually active female (13.9±1.2) adolescents from a rural Nandi primary school are assessed. Aerobic capacity ([Formula: see text]) was evaluated during two maximal discontinuous incremental exercise tests; physical activity using accelerometry combined with a global positioning system; and energy expenditure using the doubly labelled water method. The [Formula: see text] of the male and female adolescents were 73.9±5.7 ml(.) kg(-1.) min(-1) and 61.5±6.3 ml(.) kg(-1.) min(-1), respectively. Total time spent in sedentary, light, moderate and vigorous physical activities per day was 406±63 min (50% of total monitored time), 244±56 min (30%), 75±18 min (9%) and 82±30 min (10%). Average total daily distance travelled to and from school was 7.5±3.0 km (0.8-13.4 km). Mean daily energy expenditure, activity-induced energy expenditure and physical activity level was 12.2±3.4 MJ(.) day(-1), 5.4±3.0 MJ(.) day(-1) and 2.2±0.6. 70.6% of the variation in [Formula: see text] was explained by sex (partial R(2) = 54.7%) and body mass index (partial R(2) = 15.9%). Energy expenditure and physical activity variables did not predict variation in [Formula: see text] once sex had been accounted for. The highly active and energy-demanding lifestyle of rural Kenyan adolescents may account for their exceptional aerobic fitness and collectively prime them for later training and athletic success

GPS analysis of a team competing at a national Under 18 field hockey tournament

The purpose of this study was to utilise global-positioning system (GPS) technology to quantify the running demands of national Under 18 field hockey players competing in a regional field hockey tournament. Ten male players (mean ± SD; age 17.2 ± 0.4 years; stature 178.1 ± 5.2 cm; body mass 78.8 ± 8.8 kg) wore GPS units while competing in six matches over seven days at the 2018 New Zealand national under 18 field hockey tournament. GPS enabled the measurement of total distance (TD), low-speed activity (LSA; 0 -14.9 km/hr), and high-speed running (HSR; ≥ 15 km/hr) distances. Differences in running demands (TD, LSA, HSR) between positions were assessed using effect size and percent difference ± 90% confidence intervals. Midfielders covered the most TD and LSA per game and strikers the most HSR during the 6 matches. There were “very large” differences between strikers and midfielders for TD and LSA, strikers and defenders for LSA and HSR, and defenders and midfielders for LSA. These results suggest that these playing positions are sufficiently different to warrant specialised position-specific conditioning training leading into a field hockey tournament

The effects of morning preconditioning protocols on testosterone, cortisol and afternoon sprint cycling performance [conference presentation]

Opportunities exist for athletes to undertake morning exercise protocols in an attempt to potentate afternoon performance. Four sub elite track sprint cyclists completed a morning cycling (Cyc) or weights-based protocol (WP) prior to an afternoon cycling time trial (500m) in a repeated measures, counterbalance crossover design. Measured variables included heart rate, blood lactate, cycling peak power, salivary testosterone (T) and cortisol levels along with time trial performance. Standardised differences in means via magnitude-based inferences were calculated using paired samples T-tests in SPSS version 24 with statistical significance set at p < 0.05. The WP produced significantly faster times in the final 250m in comparison to CycP. The anticipated circadian decline of T was observed after the CycP but was however mitigated following the WP. While slight decreases in 500m times were experienced during the WP, they were not significant and were considered within the normal variations experienced between performances by elite athletes. The effect of the WP on the circadian rhythm of T could be linked to a greater recruitment of muscle fibres. Results suggest a morning resistance protocol can positively affect testosterone levels for afternoon performance. Possible gender and individual responses from conducting a W over Cyc protocol were observed and require further investigation

The influence of continuous vs split training protocols on endurance performance

Reports of twice daily training being used routinely by elite level endurance runners can be traced back to the 1960s. Coaches and runners have engaged in training protocols conducted during the foundational stage of training, that split the long, low intensity training (LIT) session into two sessions performed twice daily, in order to maintain volume of exercise (aligned with a single, long LIT session). Despite this, few studies to date have explored the acute physiological responses or the long-term (chronic) physiological adaptations to ‘twice daily training’. There is an assumption of parallel benefits of once daily training versus twice daily training based on total volume of exercise accumulated, however, this assumption has not been tested. The primary aim of this thesis was therefore to investigate the effects of once daily and twice daily training on factors associated with running performance. Before addressing this primary aim, a comparison of a 5 km performance TT in both the laboratory and outdoor environments was made. The laboratory is commonly used a testing ground in scientific research, however, there are often questions over the ecological validity of laboratory-based trials and their transferability into a field based competitive environment. Results generated here demonstrate that there are significant performance differences in these environments. However, participants disclosed their discomfort when testing outdoors which drove the decision to limit all testing in Studies 2 and 3 exploring differences in once and twice daily training to the laboratory. Study 1 also derived four prediction equations designed to be used by athletes and coaches. Equations 1 and 2 were to predict laboratory 5 km TT times and 4 and 5 were to predict outdoor 5 km TT times. Findings from Study 2 demonstrated that in the acute setting, significant differences are seen between once daily training and twice daily training for running economy (RE) (6.4 ± 2.9 mL.kg-1.km-1) (p = 0.033), respiratory exchange ratio (RER) (-0.05 ± 0) (p<0.001) and estimated fat metabolised (12.9 ± 2.4 grams) (p<0.001). Furthermore, the twice daily group did not reduce their velocity over the course of the day to the same degree as the once daily group. These differences provided a rationale for investigating twice daily training as part of a training plan. Findings from Study 3 demonstrated that when MTRs incorporate once or twice daily training as part of a six week training plan, significant differences were seen between the two groups in RER (-0.06) (p<0.001) and the estimated fat metabolised (13.3 grams) (p<0.001) during the long run. Study 3 found significant differences in RER and substrate utilization of MTRs who performed either once or twice daily training as part of a six week training plan. The twice daily group used more CHO in the second run when compared with the second half of the once daily group’s run. As CHO is the more efficient fuel source for high intensity exercise such as a 5Km runs this will have contributed to the faster speeds observed for this group. Furthermore, while both groups saw significant improvements in a 5 km after performing either once daily (-13 ± 27 seconds) or twice daily (-30 ± 20 seconds) training plans, the group conducting the twice daily training saw significantly greater improvements (p = 0.03). The findings in this research therefore demonstrate that, rather than previous suggestions that performance typically declines (Svedenhag & Sjodin, 1985) during the foundational stage of training where an increase in volume is achieved, conducting either of the once or twice daily training plans developed in Study 3 for six weeks resulted in improvements in 5 km RP

The Association Between Attitudes Towards High Intensity Exercise and Self-Esteem

There has been much research that has examined the association between exercise and self-esteem. Specifically, research suggests that there is a positive association of high intensity exercise, including running, weight lifting, and interval training, with self-esteem in both children and adults. However, much of this past research involved experiments where an exercise regimen was introduced to test cause and effect of exercise and self-esteem. Further, much of the past research focused on adults outside of the United States (Hasanpour, Yìğiter, Yook). I aim to test whether there are associations of preferences for and attitudes towards high intensity exercise with self-esteem among adults based on their own self-reported attitudes and preferences. In this non-experimental study, I recruited participants through social media and via emails to participate in answering a survey that included measures of self-esteem and attitudes towards exercise. Based on past research, I hypothesized that there would be positive associations of participants’ preferences for and attitudes towards high intensity exercise with self-esteem. I conducted correlational and regression analyses with survey responses from adults. I did not find a correlation between the preference for and tolderance of high-intensity exercise and self-esteem but I believe that this is because there is a difference between atittude towards exercise and the actual physical activity of exercise

Prolonged self-paced exercise in the heat - environmental factors affecting performance

In this review we examine how self-paced performance is affected by environmental heat stress factors during cycling time trial performance as well as considering the effects of exercise mode and heat acclimatization. Mean power output during prolonged cycling time trials in the heat (≥30°C) was on average reduced by 15% in the 14 studies that fulfilled the inclusion criteria. Ambient temperature per se was a poor predictor of the integrated environmental heat stress and 2 of the prevailing heat stress indices (WBGT and UTCI) failed to predict the environmental influence on performance. The weighing of wind speed appears to be too low for predicting the effect for cycling in trained acclimatized subjects, where performance may be maintained in outdoor time trials at ambient temperatures as high as 36°C (36°C UTCI; 28°C WBGT). Power output during indoor trials may also be maintained with temperatures up to at least 27°C when humidity is modest and wind speed matches the movement speed generated during outdoor cycling, whereas marked reductions are observed when air movement is minimal. For running, representing an exercise mode with lower movement speed and higher heat production for a given metabolic rate, it appears that endurance is affected even at much lower ambient temperatures. On this basis we conclude that environmental heat stress impacts self-paced endurance performance. However, the effect is markedly modified by acclimatization status and exercise mode, as the wind generated by the exercise (movement speed) or the environment (natural or fan air movement) exerts a strong influence

The psychological, psychophysical and ergogenic effects of music in sport: A review and synthesis

This is the post-print of this chapter - Copyright @ 2008 RoutledgeWe have presented two complementary conceptual approaches underlying the study and application of music in sport and exercise contexts [103, 104]. We have also established that music can be applied to sports training and competition in many different ways, and have provided 573 initial evidence for a quartic relationship between exercise heart rate and music tempo preference. One of the main demonstrated benefits of music is that it enhances psychological state, which has implications for optimising pre-competition mental state and increasing the enjoyment of training activities. Used synchronously, music can boost work output and makes repetitive tasks such as cycling or running more energy efficient. When we embarked upon our programme of research almost two decades ago, our intention was to promote more judicious use of music. The evidence that we have accumulated coupled with the findings of many other researchers from around the world, should allow athletes and practitioners to tap the psychological, psychophysical and ergogenic effects of music with greater precision

Predictability of VO2max from three commercially available devices

The Polar V800TM, A300TM, and Garmin Forerunner 235TM predict VO2max from a submaximal effort. Purpose: To examine the predictability of VO2max from two heart rate monitors (Device A and V) and a global positioning system (GPS) watch compared to measured VO2max. Methods: Forty participants, 22 males and 18 females ages 18 to 55, came to the Running Science Laboratory at Eastern Michigan University. During visit 1, participants completed a maximal graded exercise test (GXT) to determine VO2max. At visit 2, each device’s protocol was followed to estimate VO2max. Pearson correlations, repeated measures ANOVA, and a paired samples t-test were utilized to compare estimated VO2max values from the devices to measured VO2max from the GXT (p \u3c 0.05). Results: Ten participants were excluded. The GPS watch revealed a RMANOVA p-value \u3c .001 for participants with \u3e 50 ml/kg/min VO2max. Conclusion: Even though there were moderate to strong relationships, all three watches underestimated VO2max compared to measured VO2max

Bayesian Inference Federated Learning for Heart Rate Prediction

The advances of sensing and computing technologies pave the way to develop novel applications and services for wearable devices. For example, wearable devices measure heart rate, which accurately reflects the intensity of physical exercise. Therefore, heart rate prediction from wearable devices benefits users with optimization of the training process. Conventionally, Cloud collects user data from wearable devices and conducts inference. However, this paradigm introduces significant privacy concerns. Federated learning is an emerging paradigm that enhances user privacy by remaining the majority of personal data on users’ devices. In this paper, we propose a statistically sound, Bayesian inference federated learning for heart rate prediction with autoregression with exogenous variable (ARX) model. The proposed privacy-preserving method achieves accurate and robust heart rate prediction. To validate our method, we conduct extensive experiments with real-world outdoor running exercise data collected from wearable devices.Peer reviewe