Giles D. Warrington

Four‐week habituation to simulated barefoot running improves running economy when compared with shod running

The purpose of this study was to evaluate the effects of a 4‐week familiarization to simulated barefoot running (SBR) on running economy (RE) when compared with shod running. Fifteen trained male runners (age: 24 ± 4 years; stature: 177.2 ± 6.21 cm; mass: 67.99 ± 7.36 kg and VO2max 70.2 ± 5.2 mL/kg/min) were recruited. Subjects completed two RE tests, 24 h apart, in a random order, in both the SBR and shod condition (pretest) at 11 km/h and 13 km/h. Oxygen uptake, heart rate, stride frequency, and foot strike patterns were measured in both conditions. Subjects then completed a 4‐week familiarization period of SBR, before repeating the two RE tests (post‐test). At pretest, there was no significant difference in RE between SBR and shod running (P = 0.463), but following the 4‐week familiarization period, RE significantly improved by 6.9% in the SBR condition compared with shod running (46.4 ± 0.9 vs 43.2 ± 1.2 mL/kg/min; P = 0.011). A significant improvement in RE was observed in the SBR condition (8.09%) between the pretest and post‐test (47.0 ± 1.2 vs 43.2 ± 1.2 mL/kg/min; P = 0.002). RE improved in the SBR condition as a result of familiarization, and became significantly lower in SBR compared with shod running.

Nutritional, lifestyle, and weight control practices of professional jockeys.

Abstract In this study, we describe diet and lifestyle practices of professional jockeys. Participants completed a 59-item nutrition, lifestyle, and health questionnaire (n = 21) and a 7-day estimated food diary (n = 18). Acute weight loss strategies included the use of saunas (86%), exercising to induce sweating (81%), and restricted energy intake (71%). Of the smokers (38%), 56% used smoking to control weight. Most (86%) jockeys reported attaining a 2-kg weight loss for racing (if required) 24–48 h before or on the designated race-day. Mean daily energy intake (1803 ± 564 kcal) was low and appeared to provide an insufficient availability of energy for sustainment of usual daily and metabolic processes. Carbohydrate intake (3.7 ± 1.3 g · kg−1) was below recommendations for athletes. A substantial proportion of jockeys failed to meet the estimated average requirement and lower threshold intake for a number of micronutrients. Jockeys consumed well below (0–2) the recommended five daily servings of fruit and vegetables set by the World Health Organization. Pressures of the jockey lifestyle and rigid weight limits appear to encourage unhealthy weight management practices in this group and may risk long term-health.

Chronic weight control impacts on physiological function and bone health in elite jockeys.

Abstract The aim of this study was to evaluate the impact of weight restrictions on physiological function and bone health in a group of horse racing jockeys. Twenty-seven elite male jockeys participated in this study (17 flat jockeys; 10 national hunt jockeys). Participants completed a range of measurements including anthropometry, hydration analysis, bone mineral density assessment, and musculoskeletal screening. Fifty-nine percent of flat and 40% of national hunt jockeys showed osteopenia in one or more of the total body, hip or spine scans. Mean urine-specific gravity (Usg) values revealed moderate dehydration on a non-race day (Usg = 1.022 ± 0.005 and 1.021 ± 0.007 for flat and national hunt jockeys respectively). Analysis of a number of flat jockeys (n = 11) revealed marked dehydration on an official race day (Usg = 1.028 ± 0.005). Sixty-four percent of participants reported a current injury at the time of assessment. Our results reveal some worrying trends within this population. Further research is required to examine the effects of current weight control practices typically used by jockeys on both physiological and cognitive function as well as health and performance.

A 4-week instructed minimalist running transition and gait-retraining changes plantar pressure and force.

The purpose of this study is to compare changes in plantar pressure and force using conventional running shoes (CRS) and minimalist footwear (MFW) pre and post a 4‐week MFW familiarization period. Ten female runners (age: 21 ± 2 years; stature: 165.8 ± 4.5 cm; mass: 55.9 ± 3.2 kg) completed two 11 km/h treadmill runs, 24 hours apart, in both CRS and MFW (pretest). Plantar data were measured using sensory insoles for foot strike patterns, stride frequency, mean maximum force ( M ⁢ F ¯ ), mean maximum pressure ( M ⁢ P ¯ ) and eight mean maximum regional pressures. Subjects then completed a 4‐week familiarization period consisting of running in MFW and simple gait‐retraining, before repeating the tests (posttest). During the pretests, 30% of subjects adopted a forefoot strike in MFW, following familiarization this increased to 80%; no change occurred in CRS. A significant decrease in M ⁢ F ¯ in both MFW and CRS (P = 0.024) was observed from pre‐post, and a significant decrease in heel pressures in MFW. M ⁢ P ¯ was higher in MFW throughout testing (P < 0.001).A 4‐week familiarization to MFW resulted in a significant reduction in M ⁢ F ¯ in both the CRS and MFW conditions, as well as a reduction in heel pressures. Higher M ⁢ P ¯ was observed throughout testing in the MFW condition.

Physiological and metabolic characteristics of elite tug of war athletes

Objective—To determine the aerobic power (V̇o2max), body composition, strength, muscular power, flexibility, and biochemical profile of an elite international squad of tug of war athletes. Methods—Sixteen male competitors (mean (SEM) age 34 (2) years) were evaluated in a laboratory. For comparative purposes, data were analysed relative to normative data for our centre and to a group of 20 rugby forwards from the Irish international squad. Results—The tug of war participants were lighter (83.6 (3.0) v 104.4 (1.8) kg, p<0.0001) and had less lean body mass (69.4 (2.1) v 86.2 (1.2) kg) than the rugby players and had lower than normal body fat (16.7 (0.9)%); all values are mean (SEM). Aerobic power measured during a treadmill test was 55.8 (1.6) ml/kg/min for the tug of war participants compared with 51.1 (1.4) ml/kg/min for the rugby forwards (p<0.03). A composite measure of strength derived from (sum of dominant and non-dominant grip strength and back strength)/lean body mass yielded a strength/mass ratio that was 32% greater (p<0.0001) for the tug of war group than the rugby group. Dynamic leg power was lower for the tug of war group than the rugby forwards (4659.8 (151.6) v 6198.2 (105) W respectively; p<0.0001). Leg flexibility was 25.4 (2.0) cm for the tug of war group. Back flexibility was 28.6 (1.4) cm which was lower (p<0.02) than the rugby forwards 34.2 (1.5) cm. Whereas blood chemistry and haematology were normal, packed cell volume, haemoglobin concentration, and erythrocyte volume were lower in the tug of war group than in the rugby players (p<0.05). All three haematological measures correlated with muscle mass (packed cell volume, r2 = 0.37, p<0.0001; haemoglobin concentration, r2 = 0.13, p<0.05; erythrocyte volume, r2 = 0.21, p<0.01). Conclusions—The data indicate that international level tug of war participants have excellent strength and above average endurance relative to body size, but have relatively low explosive leg power and back flexibility. The data provide reference standards for the sport and may be useful for monitoring and evaluating current and future participants.

Eight weeks gait retraining in minimalist footwear has no effect on running economy

PURPOSE To evaluate the effects of an eight week combined minimalist footwear (MFW) and gait-retraining intervention on running economy (RE) and kinematics in conventional footwear runners. METHODS Twenty-three trained male runners (age: 43 ± 10 years, stature: 177.2 ± 9.2 cm, body mass: 72.8 ± 10.2 kg, V̇O2max: 56.5 ± 7.0 mL min(-1) kg(-1)) were recruited. Participants were assigned to either an intervention group (n = 13) who gradually increased exposure to MFW and also implemented gait-retraining over an eight week period. RE and kinematics were measured in both MFW and conventional running shoes (CRS) at pre-tests and eight weeks, in a random order. In contrast the control group (n = 10) had no MFW exposure or gait retraining and were only tested in CRS. RESULTS The MFW and gait re-training intervention had no effect on RE (p < .001). However, RE was significantly better in MFW (mean difference 2.72%; p = .002) at both pre and post-tests compared to CRS. Step frequency increased as a result of the intervention (+5.7 steps per minute [spm]; p < .001), and was also significantly higher in MFW vs. CRS (+7.5 spm; p < .001). CONCLUSION Whilst a better RE in MFW was observed when compared to CRS due to shoe mass, familiarization to MFW with gait-retraining was not found to influence RE.

Cellular immune activity in response to increased training of elite oarsmen prior to Olympic competition

This study investigated the changes in urinary neopterin, a biochemical marker of cellular immune activity, in elite male rowers undertaking a progressive increase in training prior to Olympic competition. Twenty-seven male rowers of the 1992 Great Britain team provided daily urine samples for a 4-week period of training that included 17 days of altitude training and 10 days of heat acclimatization. The mean (+/- S.D.) ratio of neopterin/creatinine in urine increased from pre-training values of 135 +/- 32 to a peak of 219 +/- 121 mumol neopterin per mol creatinine on day 19 of training (P < 0.05). Changes in the ratio of neopterin/creatinine with training were found to be transient and highly variable between subjects, ranging from no change to peak values five-fold greater than baseline. On the basis of the in vivo measurement of cell-mediated immunity employed in this study, we conclude that elite athletes engaged in high-intensity training prior to competition show either no change or a moderate increase in cellular immune activation.

HIIT enhances endurance performance and aerobic characteristics more than high-volume training in trained rowers

ABSTRACT This study compared the effects of long slow distance training (LSD) with high-intensity interval training (HIIT) in rowers. Nineteen well-trained rowers performed three tests before and after an 8-week training intervention: (1) 2000 m time trial; (2) seven-stage incremental step test to determine maximum oxygen uptake (O2max), power output at O2max (WO2max), peak power output (PPO), rowing economy and blood lactate indices and (3) seven-stroke power-output test to determine maximal power output (Wmax) and force (Fmax). After baseline testing, participants were randomly assigned either to a HIIT or LSD group. The LSD comprised 10 weekly aerobic sessions. The HIIT also comprised 10 weekly sessions: 8 aerobic and 2 HIIT. The HIIT sessions comprised 6–8 × 2.5 min intervals at 100% PPO with recovery time based on heart rate (HR) returning to 70% HRmax. Results demonstrated that the HIIT produced greater improvement in 2000 m time trial performance than the LSD (effect size (ES) = 0.25). Moreover, the HIIT produced greater improvements in O2max (ES = 0.95, P = 0.035) and power output at lactate threshold (WLT) (ES = 1.15, P = 0.008). Eight weeks of HIIT performed at 100% PPO is more effective than LSD in improving performance and aerobic characteristics in well-trained rowers.

Knowledge acquisition from sensor data in an equine environment

Recent advances in sensor technology have led to a rapid growth in the availability of accurate, portable and low-cost sensors. In the Sport and Health Science domains, this has been used to deploy multiple sensors in a variety of situations in order to monitor participant and environmental factors of an activity or sport. As these sensors often output their data in a raw, proprietary or unstructured format, it is difficult to identify periods of interest, such as events or actions of interest to the Sport and Exercise Physiologists. In our research, we deploy multiple sensors on horses and jockeys while they engage in horse-racing training exercises. The Exercise Physiologists aim to identify events which contribute most to energy expenditure, and classify both the horse and jockey movement using basic accelerometer sensors. We propose a metadata driven approach to enriching the raw sensor data using a series of Profiles. This data then forms the basis of user defined algorithms to detect events using an Event-Condition-Action approach. We provide an Event Definition interface which is used to construct algorithms based on sensor measurements both before and after integration. The result enables the end user to express high level queries to meet their information needs.

Expanding sensor networks to automate knowledge acquisition

The availability of accurate, low-cost sensors to scientists has resulted in widespread deployment in a variety of sporting and health environments. The sensor data output is often in a raw, proprietary or unstructured format. As a result, it is often difficult to query multiple sensors for complex properties or actions. In our research, we deploy a heterogeneous sensor network to detect the various biological and physiological properties in athletes during training activities. The goal for exercise physiologists is to quickly identify key intervals in exercise such as moments of stress or fatigue. This is not currently possible because of low level sensors and a lack of query language support. Thus, our motivation is to expand the sensor network with a contextual layer that enriches raw sensor data, so that it can be exploited by a high level query language. To achieve this, the domain expert specifies events in a tradiational event-condition-action format to deliver the required contextual enrichment.