Postactivation Potentiation for Muay Thai Kicking Performance.

ABSTRACT: Brown, L, Doyle, G, Bruce-Low, S, Domingos, S, Anthony, K, Rowan, F, and Galbraith, A. Postactivation potentiation for Muay Thai kicking performance. J Strength Cond Res 37(10): 2032-2037, 2023-The purpose of this study was to investigate the effects of postactivation potentiation (PAP) on Muay Thai kicking performance based on 3 different rest intervals. Aiming to quantify and indicate timing protocols for conditioning coaches when training athletes using PAP. 17 male (25.3 ± 3.6 years old; 179.3 ± 2.3 cm; 78.0 ± 5.2 kg), experienced Muay Thai fighters completed a standardized warm-up, including a 10-minute cycle on the Wattbike at 60 watts and 30 body mass squats for a dynamic stretch. Subjects then completed a baseline test by striking a PowerKube using the roundhouse and Teep kick techniques. PAP exercise consisted of 4 squat repetitions to maximum effort, followed by a rest period of 2, 5, or 8 minutes. Subjects then struck the PowerKube again using the roundhouse and Teep kick techniques. Rest periods were presented in a randomized order on separate days, with 72 hours between conditions. The level of significance was set at α = 0.05. Significant increases in both roundhouse (χ 2 (3) = 38.51, p < 0.05) and Teep kick (χ 2 (3) = 26.33, p < 0.05) striking power were observed when compared with baseline. For the roundhouse kick, significant differences and large effect sizes were present between all conditions except baseline and 2-minute rest. For the Teep kick, significant differences and large effect sizes were present between baseline and 5-minute rest and baseline and 8-minute rest. This indicates that PAP with 5- or 8-minute rest increased roundhouse and Teep kick power. This research reports that a PAP stimulus from a 4RM squat exercise, followed by a 5- or 8-minute rest period, enhances kick power in trained Muay Thai fighters. This technique provides a readily available, time-efficient method to enhance performance that can be built into the warm-up procedure of athletes before training or competition.

Acute Ingestion of a Commercially Available Pre-workout Supplement Improves Anaerobic Power Output and Reduces Muscular Fatigue.

The effect of a pre-workout supplement on anaerobic power output and muscular fatigue was examined. 18 participants took part in this double-blinded crossover study, reporting for testing on 3 occasions. Participants completed a 6×6 second repeated sprint test, with 20s recovery between sprints. Anaerobic power output was recorded as the highest power achieved during sprint test. Muscular fatigue was reported as a fatigue index across the six sprints ((maximum power - minimum power) ÷ total sprint time). During a baseline visit, participants consumed 250ml of water 30 minutes prior to testing, whilst in subsequent visits a taste-matched placebo (250ml water mixed with sugar-free juice) or a pre-workout supplement (250ml water mixed with one serving of 'THE PRE' myprotein.com). Anaerobic power output increased following pre-workout ingestion (pre-workout supplement, 885.8 ± 216.9W; Placebo, 853.6 ± 206.5W; Baseline, 839.3 ± 192.6W). Baseline vs pre-workout supplement (p = 0.01, g = 0.30); Placebo vs pre-workout supplement (p = 0.01, g = 0.20); Baseline vs Placebo (p = 0.59 g = 0.09). Muscular fatigue was reduced following pre-workout ingestion (Baseline, 4.92 ± 1.83W.s; Placebo, 4.39 ± 1.93W.s; pre-workout supplement, 3.31 ± 1.34W.s). Baseline vs pre-workout supplement (p = < 0.01 g = 0.98); Placebo vs pre-workout supplement (p = 0.01, g = 0.63); Baseline vs Placebo (p = 0.20, g = 0.28). Acute ingestion of a pre-workout supplement significantly improves anaerobic power output and attenuates muscular fatigue during repeated sprint cycling.

Comparison of Critical Speed and D' Derived From 2 or 3 Maximal Tests.

Purpose: The hyperbolic distance-time relationship can be used to profile running performance and establish critical speed (CS) and D' (the curvature constant of the speed-time relationship). Typically, to establish these parameters, multiple (3+) performance trials are required, which can be highly fatiguing and limit the usability of such protocols in a single training session. This study aimed to compare CS and D' calculated from a 2-trial (2-point model) and a 3-trial (3-point model) method. Methods: A total of 14 male distance runners completed 3 fixed-distance (3600, 2400, and 1200 m) time trials on a 400-m outdoor running track, separated by 30-min recoveries. Participants completed the protocol 9 times across a 12-mo period, with approximately 42 d between tests. CS and D' were calculated using all 3 distances (3-point model) and also using the 3600- and 1200-m distances only (2-point model). Results: Mean (SD) CS for both 3-point and 2-point models was 4.94 (0.32) m·s-1, whereas the values for D' were 123.3 (57.70) and 127.4 (57.34) m for the 3-point and 2-point models, respectively. Overall bias for both CS and D' between 3-point and 2-point model was classed as trivial. Conclusion: A 2-point time-trial model can be used to calculate CS and D' as proficiently as a 3-point model, making it a less fatiguing, inexpensive, and applicable method for coaches, practitioners, and athletes for monitoring running performance in 1 training session.

Transition phase clothing strategies and their effect on body temperature and 100-m swimming performance.

OBJECTIVE: Effective warm-ups are attributed to several temperature-related mechanisms. Strategies during the transition phase, preceding swimming competition, have been shown to prolong temperature-related warm-up effects. The purpose of this study was to evaluate the effects of two different clothing strategies during the transition phase, on subsequent 100-m maximal swimming performance. METHODS: Nine competitive swimmers (3 female, 21 ± 3 yrs; 6 male 20 ± 2 yrs, mean performance standard 702 FINA Points, mean 100-m seasons best time 61.54 s) completed their own 30-min individual pool warm-up, followed by 7-min changing time and a 30-min transition phase, straight into a 100-m maximal effort time-trial. During the transition phase, swimmers remained seated, either wearing warm or limited clothing. Swimmers returned 1 week later, where clothing conditions were alternated. RESULTS: Post-transition phase skin and core temperature remained higher in the warm clothing condition compared to the limited clothing condition (Mean Core: 36.90 ± 0.17°C, 36.61 ± 0.15°C, P < .01; Mean Skin: 33.49 ± 0.59°C, 31.94 ± 0.59°C, P < .01). One hundred-metre finish times were 0.6% faster in the warm clothing condition compared to the limited clothing condition (62.63 ± 7.69 s, 63.00 ± 7.75 s, P < .01). CONCLUSION: Wearing warm clothing during a 30-min transition phase improved swimming performance by 0.6%, compared to limited clothing.

A single-visit field test of critical speed.

PURPOSE: To compare critical speed (CS) measured from a single-visit field test of the distance-time relationship with the "traditional" treadmill time-to-exhaustion multivisit protocol. METHODS: Ten male distance runners completed treadmill and field tests to calculate CS and the maximum distance performed above CS (D'). The field test involved 3 runs on a single visit to an outdoor athletics track over 3600, 2400, and 1200 m. Two field-test protocols were evaluated using either a 30-min recovery or a 60-min recovery between runs. The treadmill test involved runs to exhaustion at 100%, 105%, and 110% of velocity at VO2max, with 24 h recovery between runs. RESULTS: There was no difference in CS measured with the treadmill and 30-min- and 60-minrecovery field tests (P < .05). CS from the treadmill test was highly correlated with CS from the 30- and 60-min-recovery field tests (r = .89, r = .82; P < .05). However there was a difference and no correlation in D' between the treadmill test and the 30 and 60-min-recovery field tests (r = .13; r = .33, P > .05). A typical error of the estimate of 0.14 m/s (95% confidence limits 0.09-0.26 m/s) was seen for CS and 88 m (95% confidence limits 60-169 m) for D'. A coefficient of variation of 0.4% (95% confidence limits: 0.3-0.8%) was found for repeat tests of CS and 13% (95% confidence limits 10-27%) for D'. CONCLUSION: The single-visit method provides a useful alternative for assessing CS in the field.

A 1-year study of endurance runners: training, laboratory tests, and field tests.

PURPOSE: To examine the training and concomitant changes in laboratory- and field-test performance of highly trained endurance runners. METHODS: Fourteen highly trained male endurance runners (mean ± SD maximal oxygen uptake [VO2max] 69.8 ± 6.3 mL · kg-1 · min-1) completed this 1-y training study commencing in April. During the study the runners undertook 5 laboratory tests of VO2max, lactate threshold (LT), and running economy and 9 field tests to determine critical speed (CS) and the modeled maximum distance performed above CS (D'). The data for different periods of the year were compared using repeated-measures ANOVA. The influence of training on laboratory- and field-test changes was analyzed by multiple regression. RESULTS: Total training distance varied during the year and was lower in May-July (333 ± 206 km, P = .01) and July-August (339 ± 206 km, P = .02) than in the subsequent January-February period (474 ± 188 km). VO2max increased from the April baseline (4.7 ± 0.4 L/min) in October and January periods (5.0 ± 0.4 L/min, P ≤ .01). Other laboratory measures did not change. Runners' CS was lowest in August (4.90 ± 0.32 m/s) and highest in February (4.99 ± 0.30 m/s, P = .02). Total training distance and the percentage of training time spent above LT velocity explained 33% of the variation in CS. CONCLUSION: Highly trained endurance runners achieve small but significant changes in VO2max and CS in a year. Increases in training distance and time above LT velocity were related to increases in CS.