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Heat is a major stressor during exercise, though its value in driving adaptation is not well understood. Muscle heating can upregulate pathways facilitating protein synthesis and could thereby enhance effects of exercise training, however, few studies have investigated this possibility. We examined whether heating active muscle during resistance training differentially affected physical and functional adaptations. Within a randomised contralateral-limb control study, ten healthy, resistance-untrained individuals (21 ± 3 y; 5 female) completed 30 sessions of progressive resistance training (12 weeks), performing 4 X 8 unilateral knee extensions at 70% of 1RM. One randomly-allocated thigh was heated during, and for 20 min after, each session using an electric pad eliciting muscle temperatures of >38 °C (HOT); the contralateral limb remained unheated (CON). Training intensity was progressed using 4-weekly strength assessments. Quadricep lean mass (measured using DXA) increased by 15 ± 7% in HOT (p = 0.00) and 15 ± 6% in CON (p = 0.00); the difference being trivial (p = 0.94). Peak isokinetic torque at 90°.s-1 increased by 30 ± 25% (HOT; p = 0.00) and 34 ± 33% (CON; p = 0.01), with no difference (p = 0.84) between limbs. Rate of torque development increased »40%, with no difference between limbs (p = 0.73). The increase in 3-RM strength was also similar in HOT (75 ± 16%) and CON (71 ± 14%; p = 0.80 for difference). No differences in mass or strength changes were evident between sexes. In conclusion, supplemental heating of active muscle during and after each bout of resistance training showed no clear positive (or negative) effect on training-induced hypertrophy or function. [ABSTRACT FROM AUTHOR]

Background: Heat is a major form of stress caused by exercise, though its value in driving adaptation is not well understood. Aim: Through a contralateral-limb control study we examined whether supplemental heating of active muscle during resistance training differentially affected physical and functional adaptations compared to those from traditional training without muscle heating. Methods: Ten healthy young adult volunteers (5 females) completed 12-wk progressive resistance training of the knee extensors, comprising 30 sessions of 32 repetitions (4 sets of 8) of unilateral knee extensions at 70% of legspecific 1-RM. One randomly allocated thigh was heated during and for 20 min after each training session, using a customised heat pad eliciting muscle temperatures of 38-39.5 °C. Thigh lean mass was measured at baseline and 12 weeks, and concentric knee extensor maximal isokinetic (90°.s-1) torque was measured at baseline and each 4 wk. Results: Quadriceps' lean mass increased across 12-wk training, by 15 ±7% (761 ±280 g; p=0.00) and 15 ±6% (752 ±304 g; p=0.00) in the heated and control limbs, respectively; the difference being trivial (0 ±3%; p=0.94). Peak torque increased (p=0.02) to more extent, by 33 ±38% and 35 ±37%, respectively; with an unclear difference of 2 ±17% between limbs (p=0.82). Rate of torque development increased by 47 ±44% in the heated limb (p=0.01) and 45 ±39% (p=0.08) in the control limb (difference: 2 ±18%; p=0.90). No sex differences were evident for mass or strength changes. Conclusions: Heating of the active muscle mass during and after resistance training shows no clear positive (or negative) effect on training-induced hypertrophy or the improvements in concentric isokinetic strength and rate of torque development, compared to those from resistance training without heat. [ABSTRACT FROM AUTHOR]

Due to the nature of firefighting, most effective cooling interventions to reduce heat strain and optimise performance are not practically viable. This study quantified the effects of two practical cooling strategies, co-designed with subject-matter experts, on physiological strain and physical, perceptual, and visuo-motor performance during simulated firefighting in the heat. Randomised cross-over. On three occasions 14 firefighters completed an 80-min simulation in a hot-humid environment (32.0[0.9]°C, 59[3]%RH) including two 20-min firefighting tasks in full protective clothing, each followed by 20-min seated recovery. Recovery involved removal of protective clothing and one of three interventions – control (CON; ambient-temperature water consumption), basic (BASIC; cool-water consumption, ambient-forearm immersion/towels, fan), and advanced (ADV; ice-slushy consumption, cool-forearm immersion/ice packs, misting-fan). Thermal (core temperature) and cardiovascular (heart rate, arterial pressure) responses were measured throughout, whilst physical (handgrip/balance), visuo-motor (reaction time/memory recall) and perceptual (fatigue/thermal sensation/comfort) measures were assessed pre- and post-trial. Compared to CON, core temperature was lower in BASIC and ADV following the second task (ADV: 37.7[0.4]; BASIC: 38.0[0.4]; CON: 38.3[0.4]°C) and recovery protocol (ADV: 37.5[0.3]; BASIC: 37.7 [0.3] CON: 38.3[0.4]°C). This was paralleled by lowered heart rate, rate pressure product, and thermal sensation following the recovery protocols, in the ADV and BASIC condition compared to CON (p <.05). No physical or visuo-motor outcomes differed significantly between conditions. Whilst these observations need to be extended to field conditions, our findings demonstrate that two novel cooling interventions developed in collaboration with subject-matter experts offered benefits for reducing thermal strain and optimising firefighter safety. • A combination of cooling methods showed significant reductions in core temperature. • These results will help design education and dissemination of cooling interventions. • Future research should examine visuo-motor performance as a function of heat stress. [ABSTRACT FROM AUTHOR]

Purpose: To compare the training characteristics of an elite team pursuit cycling squad in the 3-month preparation phases prior to 2 successive world-record (WR) performances., Methods: Training data of 5 male track endurance cyclists (mean [SD]; age 23.4 [3.46] y; body mass 80.2 [2.74] kg; 4.5 [0.17] W·kg-1 at LT2; maximal aerobic power 6.2 [0.27] W·kg-1; maximal oxygen uptake 65.9 [2.89] mL·kg-1·min-1) were analyzed with weekly total training volume by training type and heart rate, power output, and torque intensity distributions calculated with reference to the respective WRs' performance requirements., Results: Athletes completed 805 (82.81) and 725 (68.40) min·wk-1 of training, respectively, in each season. In the second season, there was a 32% increase in total track volume, although track sessions were shorter (ie, greater frequency) in the second season. A pyramidal intensity distribution was consistent across both seasons, with 81% of training, on average, performed below LT1 power output each week, whereas 6% of training was performed above LT2. Athletes accumulated greater volume above WR team pursuit lead power (2.4% vs 0.9%) and torque (6.2% vs 3.2%) in 2019. In one athlete, mean single-leg-press peak rate of force development was 71% and 46% higher at mid- and late-phases, respectively, during the preparation period., Conclusions: These findings provide novel insights into the common and contrasting methods contributing to successive WR team pursuit performances. Greater accumulation of volume above race-specific power and torque (eg, team pursuit lead), as well as improved neuromuscular force-generating capacities, may be worthy of investigation for implementation in training programs.

Purpose: To profile the training characteristics of an elite team pursuit cycling squad and assess variations in training intensity and load accumulation across the 36-week period prior to a world-record performance at the 2018 Commonwealth Games., Methods: Training data of 5 male track endurance cyclists (mean [SD]; age 21.9 [3.52] y; 4.4 [0.16] W·kg-1 at anaerobic threshold; 6.2 [0.28] W·kg-1 maximal oxygen uptake 68.7 [2.99] mL kg·min-1) were analyzed with weekly total training volume and heart rate, power output, and torque intensity distributions calculated with reference to their 3:49.804 min:s.ms performance requirements for a 4-km team pursuit., Results: Athletes completed 543 (37) h-1 of training across 436 (16) sessions. On-bike activities accounted for 69.9% of all training sessions, with participants cycling 11,246 (1139) km-1 in the training period of interest, whereas 12.7% of sessions involved gym/strength training. A pyramidal intensity distribution was evident with over 65% and 70% of training, respectively, performed at low-intensity zone heart rate and power output, whereas 5.3% and 7.7% of training was performed above anaerobic threshold. The athletes accumulated 4.4% of total training volume at, or above, their world-record team pursuit lead position torque (55 N·m)., Conclusions: These data provide updated and novel insight to the power and torque demands and load accumulation contributing to world-record team pursuit performance. Although the observed pyramidal intensity distribution is common in endurance sports, the lack of shift toward a polarized intensity distribution during taper and competition peaking differs from previous research.

Heat is a major stressor during exercise, though its value in driving adaptation is not well understood. Muscle heating can upregulate pathways facilitating protein synthesis and could thereby enhance effects of exercise training, however, few studies have investigated this possibility. We examined whether heating active muscle during resistance training differentially affected physical and functional adaptations. Within a randomised contralateral-limb control study, ten healthy, resistance-untrained individuals (21 ± 3 y; 5 female) completed 30 sessions of progressive resistance training (12 weeks), performing 4 × 8 unilateral knee extensions at 70% of 1RM. One randomly-allocated thigh was heated during, and for 20 min after, each session using an electric pad eliciting muscle temperatures of >38 °C (HOT); the contralateral limb remained unheated (CON). Training intensity was progressed using 4-weekly strength assessments. Quadricep lean mass (measured using DXA) increased by 15 ± 7% in HOT ( p = 0.00) and 15 ± 6% in CON ( p = 0.00); the difference being trivial ( p = 0.94). Peak isokinetic torque at 90°.s -1 increased by 30 ± 25% (HOT; p = 0.00) and 34 ± 33% (CON; p = 0.01), with no difference ( p = 0.84) between limbs. Rate of torque development increased ∼40%, with no difference between limbs ( p = 0.73). The increase in 3-RM strength was also similar in HOT (75 ± 16%) and CON (71 ± 14%; p = 0.80 for difference). No differences in mass or strength changes were evident between sexes. In conclusion, supplemental heating of active muscle during and after each bout of resistance training showed no clear positive (or negative) effect on training-induced hypertrophy or function.