BackgroundThis study evaluated cognitive workload in soldiers undertaking a long duration march wearing different loads.MethodsMilitary participants (n=12 men and n=10 women) performed four 3-hour loaded marches (12.25 km at 4.9 km/hour) wearing either 21 kg, 26 kg, 33 kg or 43 kg. During the march, accuracy and response time were measured using the verbal working memory n-back test (0, 1, 2 and 3) and two bespoke Go/No Go tests (visual/auditory) to assess inhibition of a pre-potent response.ResultsThe physical demands of the march increased with load and march duration but remained at moderate intensity. N-back test accuracy ranged from 74% to 98% in men and 62% to 98% in women. Reduced accuracy was observed as load and time increased. Accuracy during the visual Go/No Go test also reduced with load, accuracy ranged from 69% to 89% in men and 65% to 90% in women. No differences due to load or time were observed during completion of the auditory Go/No Go task; accuracy ranged from 93% to 97% in men and 77% to 95% in women. A number of participants were unable to complete the march due to discomfort. Reports of discomfort were more frequent in women, which may have contributed to the greater reductions in accuracy observed.ConclusionThese data provide further evidence that cognitive performance of military personnel can be affected during long duration loaded marching. Women reported discomfort from equipment more frequently than men, which may make them more susceptible to declines in cognitive performance. These findings highlight important considerations for equipment procurement.

Purpose: Determine the effects of skin temperature change on bench-pull power following a passive warm-up intervention with highly trained swimmers using multiple heated clothing garments. Methods: Using a crossover design, 8 high-performance swimmers (mean [SD]; age, 22.4 [4.4] y; body mass, 74.9 [8.1] kg; height, 1.79 [0.09] m; world record ratio, 107.3% [5.1%]) completed a pool-based warm-up followed by a 35-minute transition phase before completing 3 repetitions at 50% of 1-repetition maximum of the bench-pull exercise. During transition, swimmers wore either a warm (control) or a heated (heat) clothing condition. Results: Following heating, mean skin temperature was 0.7 °C higher in heat (P = .011), though no change was seen in tympanic temperature. Bench-pull mean and peak power improved by 4.5% and 4.7% following heating, respectively. A large repeated-measures correlation was observed between skin temperature and mean (r [90% CI] = .94 [.65 to .99], P < .01) and peak (r [90% CI] = .89 [.45 to .98], P < .01) power output. Thermal sensation and comfort at all regions were higher with heating (P ≤ .02). Conclusion: Combined upper- and lower-limb passive heating can increase whole-body skin temperature and improve short-duration upper-limb power output during the bench-pull exercise. Improvements in power output were directly related to the skin temperature increase facilitated by the heated clothing.

Background In swimming, the period between the end of the swimming warmup and the beginning of competition is critical to performance, here termed the transition phase. Several options are available during this phase, necessitating a systematic review to understand if optimal strategies exist. Objectives To synthesise and critically evaluate the current literature investigating land-based warmup interventions on subsequent performance in competitive swimmers. Methods A search of three electronic databases (PubMed, EBSCO SPORTDiscus and Web of Science) was conducted to identify original studies until February 2022. Selection criteria dictated that (i) a control condition was used, (ii) participants were ≥ 15 years of age, (iii) a pool-based warmup was done prior to the land-based warmup. A total of 25 articles met the selection criteria. Results Reducing the transition phase duration by at least half led to consistently faster time-trial times of between 1.1–1.5% for all included studies. Passive warmups using clothing interventions resulted in mostly faster time-trial’s of 0.4–0.8% with increases in skin temperature frequent, though little change occurred in core temperature. The methodology of passive respiratory warmups were vastly different with positive time-trial’s effects ranging between 0.9–1.1% for two studies, though one reported no meaningful difference. Active warmups led to consistently faster time-trial’s between 0.7–0.9%, though the unpinning factors are not clear. Warmups which combined passive and active options frequently led to faster time-trial’s between 0.8–3%. Upper and combined limb post-activation performance enhancement led to mostly unfavourable time-trial changes. Lower limb exclusive protocols results were inconsistent, with limited beneficial effects on time-trial or start performance reported following plyometric protocols. However, there does appear merit in heavier loaded lower limb protocols. Conclusion Each of a reduced transition phase length, and passive, active or combination warmup have demonstrated improvements in swimming performance. Conversely, PAPE protocols should be used with caution, especially when including the upper limbs.