PurposeTo characterise hydration, cooling, body mass loss, and core (Tcore) and skin (Tsk) temperatures during World Athletics Championships in hot-humid conditions.MethodsMarathon and race-walk (20 km and 50 km) athletes (n=83, 36 women) completed a pre-race questionnaire. Pre-race and post-race body weight (n=74), Tcore (n=56) and Tsk (n=49; thermography) were measured.ResultsMost athletes (93%) had a pre-planned drinking strategy (electrolytes (83%), carbohydrates (81%)) while ice slurry was less common (11%; p<0.001). More men than women relied on electrolytes and carbohydrates (91%–93% vs 67%–72%, p≤0.029). Drinking strategies were based on personal experience (91%) rather than external sources (p<0.001). Most athletes (80%) planned pre-cooling (ice vests (53%), cold towels (45%), neck collars (21%) and ice slurry (21%)) and/or mid-cooling (93%; head/face dousing (65%) and cold water ingestion (52%)). Menthol usage was negligible (1%–2%). Pre-race Tcore was lower in athletes using ice vests (37.5°C±0.4°C vs 37.8°C±0.3°C, p=0.024). Tcore (pre-race 37.7°C±0.3°C, post-race 39.6°C±0.6°C) was independent of event, ranking or performance (p≥0.225). Pre-race Tsk was correlated with faster race completion (r=0.32, p=0.046) and was higher in non-finishers (did not finish (DNF); 33.8°C±0.9°C vs 32.6°C±1.4°C, p=0.017). Body mass loss was higher in men than women (−2.8±1.5% vs −1.3±1.6%, p<0.001), although not associated with performance.ConclusionMost athletes’ hydration strategies were pre-planned based on personal experience. Ice vests were the most adopted pre-cooling strategy and the only one minimising Tcore, suggesting that event organisers should be cognisant of logistics (ie, freezers). Dehydration was moderate and unrelated to performance. Pre-race Tsk was related to performance and DNF, suggesting that Tsk modulation should be incorporated into pre-race strategies.

The aim of the study was to examine the effects of three different loads (LOAD) in combination with four different exercise modes (MODE) on physiological responses during and after one fatiguing bout of bench press exercise. Ten resistance-trained healthy male subjects performed bench press exercise each at 55% (LOW), 70% (MID) and 85% (HIGH) of 1 repetition maximum (1RM) for as many repetitions as possible and in four training modes: 4-1-4-1 (4-s concentric, 1-s isometric, 4-s eccentric and 1-s isometric successive actions), 2-1-2-1, 1-1-1-1 and MAX (maximum velocity concentric). Oxygen uptake [Formula: see text] was measured during exercise and for 30-min post-exercise. Maximum blood lactate concentration (blood LA(max)) and heart rate (HR(max)) were also determined. Number of repetitions (REPS) and exercise time (EXTIME) were recorded and accumulated lifted mass (MASS), defined by REPS × lifted mass, was calculated. LOAD had a significant effect on REPS (LOW > MID > HIGH, p < 0.01). A significant increase of REPS was obtained exercising at a faster MODE except from 1-1-1-1 to MAX (p < 0.01). EXTIME significantly decreased with increasing LOAD (LOW > MID > HIGH, p < 0.01 for all) and faster MODE (4-1-4-1, 2-1-2-1, 1-1-1-1 > MAX; p > 0.01). MASS decreased significantly with increasing LOAD (p < 0.01) but increased with a faster MODE (p < 0.05) with the exception of 1-1-1-1 to MAX. MODE had a significant effect on VO(2) (4-1-4-1 > MAX; p < 0.05). LOAD had a significant effect on consumed O(2) during exercise (LOW > MID and HIGH; p > 0.01) and on blood LA(max) (LOW and MID > HIGH; p < 0.01). The data indicate that physiological responses on different resistance exercises depend on both the load and the velocity mode.

PurposeTo determine associations between thermal responses, medical events, performance, heat acclimation and health status during a World Athletics Championships in hot-humid conditions.MethodsFrom 305 marathon and race-walk starters, 83 completed a preparticipation questionnaire on health and acclimation. Core (Tcore; ingestible pill) and skin (Tskin; thermal camera) temperatures were measured in-competition in 56 and 107 athletes, respectively. 70 in-race medical events were analysed retrospectively. Performance (% personal best) and did not finish (DNF) were extracted from official results.ResultsPeak Tcore during competition reached 39.6°C±0.6°C (maximum 41.1°C). Tskin decreased from 32.2°C±1.3°C to 31.0°C±1.4°C during the races (p<0.001). Tcore was not related to DNF (25% of starters) or medical events (p≥0.150), whereas Tskin, Tskin rate of decrease and Tcore-to-Tskin gradient were (p≤0.029). A third of the athletes reported symptoms in the 10 days preceding the event, mainly insomnia, diarrhoea and stomach pain, with diarrhoea (9% of athletes) increasing the risk of in-race medical events (71% vs 17%, p<0.001). Athletes (63%) who performed 5–30 days heat acclimation before the competition: ranked better (18±13 vs 28±13, p=0.009), displayed a lower peak Tcore (39.4°C±0.4°C vs 39.8°C±0.7°C, p=0.044) and larger in-race decrease in Tskin (−1.4°C±1.0°C vs −0.9°C±1.2°C, p=0.060), than non-acclimated athletes. Although not significant, they also showed lower DNF (19% vs 30%, p=0.273) and medical events (19% vs 32%, p=0.179).ConclusionTskin, Tskin rate of decrease and Tcore-to-Tskin gradient were important indicators of heat tolerance. While heat-acclimated athletes ranked better, recent diarrhoea represented a significant risk factor for DNF and in-race medical events.

BackgroundThe purpose of this study was to describe professional soccer players’ perceptions towards injuries, physical recovery and the effect of surface related factors on injury resulting from soccer participation on 3rd generation artificial turf (FT) compared to natural grass (NG).MethodsInformation was collected through a questionnaire that was completed by 99 professional soccer players from 6 teams competing in Major League Soccer (MLS) during the 2011 season.ResultsThe majority (93% and 95%) of the players reported that playing surface type and quality influenced the risk of sustaining an injury. Players believed that playing and training on FT increased the risk of sustaining a non-contact injury as opposed to a contact injury. The players identified three surface related risk factors on FT, which they related to injuries and greater recovery times: 1) Greater surface stiffness 2) Greater surface friction 3) Larger metabolic cost to playing on artificial grounds. Overall, 94% of the players chose FT as the surface most likely to increase the risk of sustaining an injury.ConclusionsPlayers believe that the risk of injury differs according to surface type, and that FT is associated with an increased risk of non-contact injury. Future studies should be designed prospectively to systematically track the perceptions of groups of professional players training and competing on FT and NG.

The purpose of the study was to compare the mechanical impact and the corresponding physiological responses of 4 different and often practically applied resistance training methods (RTMs). Ten healthy male subjects (27.3 ± 3.2 years) experienced in resistance training performed 1 exhausting set of bench press exercise until exhaustion for each of the following RTMs: strength endurance (SE), fast force endurance (FFE), hypertrophy (HYP), and maximum strength (MAX). The RTMs were defined by different lifting masses and different temporal distributions of the contraction modes per repetition. Mean concentric power (P), total concentric work (W), and exercise time (EXTIME) were determined. Oxygen uptake (V[Combining Dot Above]O2) was measured during exercise and for 30 minutes postexercise. Mean V[Combining Dot Above]O2, volume of consumed O2, and excess postexercise oxygen consumption (EPOC) were calculated over 30 minutes of recovery. Maximum blood lactate concentration (LAmax) was also determined postexercise. The P was significantly higher (p < 0.01) for FFE and MAX compared with that for SE and HYP. The W was significantly higher for FFE than for all other RTMs (p < 0.01), and it was also lower for SE than for MAX (p < 0.05). EXTIME for SE was significantly higher (p < 0.01) than for all other RTMs, whereas EXTIME for MAX was significantly lower (p < 0.01) than for all other RTMs. Mean V[Combining Dot Above]O2 was significantly higher during FFE than during all other RTMs (p < 0.01). Consumed O2 was significantly higher (p < 0.05) during SE than for HYP and MAX, and it was also significantly higher for FFE and HYP compared with MAX (p < 0.05). The LAmax was significantly higher after FFE than after MAX (p < 0.05). There were no significant differences in EPOC between all RTMs. The results indicate that FFE and MAX are adequate to train muscular power despite the discrepancy in the external load. Because FFE performance achieves the highest amount in mechanical work, it may also elicit the highest total energy expenditure. The FFE challenges aerobic metabolism most and SE enables the longest EXTIME, indicating both are appropriate to enhance aerobic muscular capacities. The EPOC and LA values may indicate that energy needs covered by anaerobic metabolism are not higher during HYP and MAX compared with the RTM of lower external load.