The interactive effect of sustained sleep restriction and resistance exercise on skeletal muscle transcriptomics in young females.

Both sleep loss and exercise regulate gene expression in skeletal muscle, yet little is known about how the interaction of these stressors affects the transcriptome. The aim of this study was to investigate the effect of nine nights of sleep restriction (SR), with repeated resistance exercise (REx) sessions, on the skeletal muscle transcriptome of young, trained females. Ten healthy females aged 18-35 yr old undertook a randomized cross-over study of nine nights of SR (5 h time in bed) and normal sleep (NS; ≥7 h time in bed) with a minimum 6-wk washout. Participants completed four REx sessions per condition (days 3, 5, 7, and 9). Muscle biopsies were collected both pre- and post-REx on days 3 and 9. Gene and protein expression were assessed by RNA sequencing and Western blot, respectively. Three or nine nights of SR had no effect on the muscle transcriptome independently of exercise. However, close to 3,000 transcripts were differentially regulated (false discovery rate < 0.05) 48 h after the completion of three resistance exercise sessions in both NS and SR conditions. Only 39% of downregulated genes and 18% of upregulated genes were common between both conditions, indicating a moderating effect of SR on the response to exercise. SR and REx interacted to alter the enrichment of skeletal muscle transcriptomic pathways in young, resistance-trained females. Performing exercise when sleep restricted may not provide the same adaptive response for individuals as if they were fully rested.NEW & NOTEWORTHY This study investigated the effect of nine nights of sleep restriction, with repeated resistance exercise sessions, on the skeletal muscle transcriptome of young, trained females. Sleep restriction and resistance exercise interacted to alter the enrichment of skeletal muscle transcriptomic pathways in young, resistance-trained females. Performing exercise when sleep restricted may not provide the same adaptive response for individuals as if they were fully rested.

"We know what we should be eating, but we don't always do that." How and why people eat the way they do: a qualitative study with rural australians.

BACKGROUND: There is evidence that most people are aware of the importance of healthy eating and have a broad understanding regarding types of food that enhance or detract from health. However, greater health literacy does not always result in healthier eating. Andreasen's Social Marketing Model and Community-Based Social Marketing both posit that, in order to change health behaviours, it is crucial to understand reasons for current behaviours and perceived barriers and benefits to improved behaviours. Limited research has been conducted, however, that explores these issues with general populations. This study aimed to help address this gap in the evidence using a qualitative methodology. METHODS: Three group discussions were conducted with a total of 23 participants: (1) young women aged 18-24 with no children; (2) women aged 35-45 with primary school aged children; and (3) men aged 35-50 living with a partner and with pre- or primary school aged children. The discussions took place in a regional centre of Victoria, Australia. Transcriptions were thematically analysed using an inductive descriptive approach and with reference to a recent integrated framework of food choice that identified five key interrelated determinants: food- internal factors; food- external factors; personal-state factors; cognitive factors; and sociocultural factors. RESULTS: We found that food choice was complex, with all five determinants evident from the discussions. However, the "Social environment" sub-category of "Food-external factors", which included family, work, and social structures, and expectations (or perceived expectations) of family members, colleagues, friends, and others, was particularly prominent. Knowledge that one should practice healthy eating, which falls under the "Cognitive factor" category, while seen as an aspiration by most participants, was often viewed as unrealistic, trumped by the need and/or desire for convenience, a combination of Food-external factor: Social environment and Personal-state factor: Psychological components. CONCLUSIONS: We found that decisions regarding what, when, and how much to eat are seen as heavily influenced by factors outside the control of the individual. It appears, therefore, that a key to improving people's eating behaviours is to make it easy to eat more healthfully, or at least not much harder than eating poorly.

Effect of repeated post-resistance exercise cold or hot water immersion on in-season inflammatory responses in academy rugby players: a randomised controlled cross-over design.

PURPOSE: Uncertainty exists if post-resistance exercise hydrotherapy attenuates chronic inflammatory and hormone responses. The effects of repeated post-resistance exercise water immersion on inflammatory and hormone responses in athletes were investigated. METHODS: Male, academy Super Rugby players (n = 18, 19.9 ± 1.5 y, 1.85 ± 0.06 m, 98.3 ± 10.7 kg) participated in a 12-week programme divided into 3 × 4-week blocks of post-resistance exercise water immersion (either, no immersion control [CON]; cold [CWI]; or hot [HWI] water immersion), utilising a randomised cross-over pre-post design. Fasted, morning blood measures were collected prior to commencement of first intervention block, and every fourth week thereafter. Linear mixed-effects models were used to analyse main (treatment, time) and interaction effects. RESULTS: Repeated CWI (p = 0.025, g = 0.05) and HWI (p < 0.001, g = 0.62) reduced creatine kinase (CK), compared to CON. HWI decreased (p = 0.013, g = 0.59) interleukin (IL)-1ra, compared to CON. HWI increased (p < 0.001-0.026, g = 0.06-0.17) growth factors (PDGF-BB, IGF-1), compared to CON and CWI. CWI increased (p = 0.004, g = 0.46) heat shock protein-72 (HSP-72), compared to HWI. CONCLUSION: Post-resistance exercise CWI or HWI resulted in trivial and moderate reductions in CK, respectively, which may be partly due to hydrostatic effects of water immersion. Post-resistance exercise HWI moderately decreased IL-1ra, which may be associated with post-resistance exercise skeletal muscle inflammation influencing chronic resistance exercise adaptive responses. Following post-resistance exercise water immersion, CWI increased HSP-72 suggesting a thermoregulatory response indicating improved adaptive inflammatory responses to temperature changes, while HWI increased growth factors (PDGF-BB, IGF-1) indicating different systematic signalling pathway activation. Our data supports the continued use of post-resistance exercise water immersion recovery strategies of any temperature during in-season competition phases for improved inflammatory adaptive responses in athletes.

Application of mobility training methods in sporting populations: A systematic review of performance adaptations.

This systematic review investigates influences of mobility training in sporting populations on performance outcomes. The search strategy involved Embase, MEDLINE Complete, Sports Discus and manual search from inception to March 2022. Mobility training studies with a minimum three-week, or 10-session duration in healthy sporting populations of any age were included. Twenty-two studies comprising predominantly young adult or junior athletes were analysed from 319 retrieved articles. Performance outcomes were strength, speed, change of direction, jumping, balance, and sport-specific skills. Fifteen studies randomized participants with only four indicating systematic allocation concealment and blinding of outcomes assessors in only one study. In 20 of 22 studies mobility training was of some benefit or helped to maintain sports performance to a larger degree than control conditions. Control conditions, which were generally no activity conditions, were primarily non-significant. The majority of evidence suggests that a range of mobility training methods may improve key sports performance variables or are unlikely to impair performance over time. Therefore, coaches can consider the potential benefits of including comprehensive mobility programmes with minimal risk of impairing performance. Higher-quality studies in homogenous populations are necessary to confirm performance changes.

No effect of repeated post-resistance exercise cold or hot water immersion on in-season body composition and performance responses in academy rugby players: a randomised controlled cross-over design.

PURPOSE: Following resistance exercise, uncertainty exists as to whether the regular application of cold water immersion attenuates lean muscle mass increases in athletes. The effects of repeated post-resistance exercise cold versus hot water immersion on body composition and neuromuscular jump performance responses in athletes were investigated. METHODS: Male, academy Super Rugby players (n = 18, 19.9 ± 1.5 y, 1.85 ± 0.06 m, 98.3 ± 10.7 kg) participated in a 12-week (4-week × 3-intervention, i.e., control [CON], cold [CWI] or hot [HWI] water immersion) resistance exercise programme, utilising a randomised cross-over pre-post-design. Body composition measures were collected using dual-energy X-ray absorptiometry prior to commencement and every fourth week thereafter. Neuromuscular squat (SJ) and counter-movement jump (CMJ) performance were measured weekly. Linear mixed-effects models were used to analyse main (treatment, time) and interaction effects. RESULTS: There were no changes in lean (p = 0.960) nor fat mass (p = 0.801) between interventions. CON (p = 0.004) and CWI (p = 0.003) increased (g = 0.08-0.19) SJ height, compared to HWI. There were no changes in CMJ height (p = 0.482) between interventions. CONCLUSION: Repeated post-resistance exercise whole-body CWI or HWI does not attenuate (nor promote) increases in lean muscle mass in athletes. Post-resistance exercise CON or CWI results in trivial increases in SJ height, compared to HWI. During an in-season competition phase, our data support the continued use of post-resistance exercise whole-body CWI by athletes as a recovery strategy which does not attenuate body composition increases in lean muscle mass, while promoting trivial increases in neuromuscular concentric-only squat jump performance.

Acute Performance, Daily Well-Being, and Hormone Responses to Water Immersion After Resistance Exercise in Junior International and Subelite Male Volleyball Athletes.

ABSTRACT: Horgan, BG, Tee, N, West, NP, Drinkwater, EJ, Halson, SL, Colomer, CME, Fonda, CJ, Tatham, J, Chapman, DW, and Haff, GG. Acute performance, daily well-being and hormone responses to water immersion after resistance exercise in junior international and subelite male volleyball athletes. J Strength Cond Res 37(8): 1643-1653, 2023-Athletes use postexercise hydrotherapy strategies to improve recovery and competition performance and to enhance adaptative responses to training. Using a randomized cross-over design, the acute effects of 3 postresistance exercise water immersion strategies on perceived recovery, neuromuscular performance, and hormone concentrations in junior international and subelite male volleyball athletes ( n = 18) were investigated. After resistance exercise, subjects randomly completed either 15-minute passive control (CON), contrast water therapy (CWT), cold (CWI), or hot water immersion (HWI) interventions. A treatment effect occurred after HWI; reducing perceptions of fatigue (HWI > CWT: p = 0.05, g = 0.43); improved sleep quality, compared with CON ( p < 0.001, g = 1.15), CWI ( p = 0.017, g = 0.70), and CWT ( p = 0.018, g = 0.51); as well as increasing testosterone concentration (HWI > CWT: p = 0.038, g = 0.24). There were trivial to small ( p < 0.001-0.039, g = 0.02-0.34) improvements (treatment effect) in jump performance (i.e., squat jump and countermovement jump) after all water immersion strategies, as compared with CON, with high variability in the individual responses. There were no significant differences (interaction effect, p > 0.05) observed between the water immersion intervention strategies and CON in performance ( p = 0.153-0.99), hormone ( p = 0.207-0.938), nor perceptual ( p = 0.368-0.955) measures. To optimize recovery and performance responses, e.g., during an in-season competition phase, postresistance exercise HWI may assist with providing small-to-large improvements for up to 38 hours in perceived recovery (i.e., increased sleep quality and reduced fatigue) and increases in circulating testosterone concentration. Practitioners should consider individual athlete neuromuscular performance responses when prescribing postexercise hydrotherapy. These findings apply to athletes who aim to improve their recovery status, where postresistance exercise HWI optimizes sleep quality and next-day perceptions of fatigue.

Improving the accuracy of self-reported height and weight in surveys: an experimental study.

BACKGROUND: Many studies rely on self-reported height and weight. While a substantial body of literature exists on misreporting of height and weight, little exists on improving accuracy. The aim of this study was to determine, using an experimental design and a comparative approach, whether the accuracy of self-reported height and weight data can be increased by improving how these questions are asked in surveys, drawing on the relevant evidence from the psychology and survey research literatures. METHODS: Two surveys from two separate studies were used to test our hypotheses (Science Survey, n = 1,200; Eating Behaviours Survey, n = 200). Participants were randomly assigned to one of six conditions, four of which were designed to improve the accuracy of the self-reported height and weight data ("preamble"), and two of which served as the control conditions ( "no preamble"). Four hypotheses were tested: (H1) survey participants read a preamble prior to being asked their height and weight will report lower heights and higher weights than those not read a preamble; (H2) the impact of question-wording (i.e., preamble vs. no preamble) on self-reported weight will be greater for participants with higher BMIs; (H3) the impact of question-wording on height will be greater for older participants; (H4) either version of the weight question - standard or "weight-specific"-may result in participants reporting more accurate self-reported weight. One-way MANOVA was conducted to test Hypothesis 1; two-way analysis of variance were conducted to test Hypothesis 2; moderation analysis was used to test Hypothesis 3; independent samples t-test was conducted to test Hypothesis 4. RESULTS: None of the hypotheses was supported. CONCLUSIONS: This paper provides an important starting point from which to inform further work exploring how question wording can improve self-reported measurement of height and weight. Future research should explore how question preambles may or may not operationalise hypothesised underlying mechanisms, the sensitivity or intrusiveness of height and weight questions, individual beliefs about one's height and weight, and survey context.

Improved power clean performance with the hook-grip is not due to altered force-time or horizontal bar-path characteristics.

he underlying biomechanical benefits of hook-grip (HG) over conventional closed-grip (CG) remain unclear. This study compared bar-path kinematics and force-time variables of the power clean (PC) performed with HG or CG. We also aimed to compared kinetic changes measured by force platform versus linear position transducer (LPT). Eleven well-trained men volunteered. Following a familiarisation session, HG, and CG 1RM conditions, were randomly completed seven days apart. System kinetics and barbell kinematics were recorded via synchronized force platform+LPT system and two-dimensional motion-capture. Statistical parametric mapping (SPM), analysis of variance, and standardised differences were utilised. The SPM cut-offs were determined via novel combination of force and displacement. No between-condition differences in normalised force-time variables of the pull or catch were detected. The first and second pull duration was similar between conditions (ES = 0.04-0.38). Conversely, catch and total PC durations were shorter at 80-95% (ES = 0.26-0.75), with the weightless phase more prolonged at 95% and 100% (ES = 0.54-0.76) with HG compared to CG. Improved timing of the turnover and catch phases appears to be the primary difference between HG and CG performance. Thus, grip type is possibly irrelevant to non-weightlifting athletes when performing submaximal catch-less derivatives..

Different Cluster-Loading Protocols Have No Effect on Intraset and Interset Power Expression.

ABSTRACT: Dudley, CE, Drinkwater, EJ, and Feros, SA. Different cluster-loading protocols have no effect on intraset and interset power expression. J Strength Cond Res 36(7): 1763-1769, 2022-This study investigated the effect of cluster-loading protocols on changes in hang power clean (HPC) power characteristics. Ten trained weightlifters (7 male, 3 female, HPC 1.28 [M]; 1.03 [F] × body mass) completed 4 experimental protocols in a randomized repeated-measures design. Protocols were traditional, a basic cluster, and 2 undulating clusters. Each protocol comprised 3 sets of 5 HPC repetitions at an average of 70% 1 repetition maximum (RM). The load for undulating cluster protocols ranged between 60 and 80% 1RM. Countermovement jumps (CMJs) were performed before and after each protocol to gauge effect on neuromuscular status. Statistical analysis comprised a one-way repeated measures analysis of variance. Peak power was significantly greater in the fifth repetition of the basic cluster set protocol compared with the traditional set protocol (mean ± SD: 6.6 ± 2.8%, p = 0.043, g = 0.25). Neither undulating load protocol significantly altered set power characteristics compared with basic cluster sets; however, when analyzing repetition data, peak power increased as load increased (and vice versa), indicating the prescribed loads were suboptimal for power expression in this sample. There was no change in CMJ height between protocols. Coaches should prescribe inter-repetition rest to maintain peak power across multiple repetitions and sets. Basic cluster protocols seem to be the most practical choice over undulating cluster protocols because there is no need to adjust load between repetitions.

Acute Inflammatory, Anthropometric, and Perceptual (Muscle Soreness) Effects of Postresistance Exercise Water Immersion in Junior International and Subelite Male Volleyball Athletes.

ABSTRACT: Horgan, BG, West, NP, Tee, N, Drinkwater, EJ, Halson, SL, Vider, J, Fonda, CJ, Haff, GG, and Chapman, DW. Acute inflammatory, anthropometric, and perceptual (muscle soreness) effects of postresistance exercise water immersion in junior international and subelite male volleyball athletes. J Strength Cond Res 36(12): 3473-3484, 2022-Athletes use water immersion strategies to recover from training and competition. This study investigated the acute effects of postexercise water immersion after resistance exercise. Eighteen elite and subelite male volleyball athletes participated in an intervention using a randomized cross-over design. On separate occasions after resistance exercise, subjects completed 1 of 4 15-minute interventions: control (CON), cold water immersion (CWI), contrast water therapy (CWT), or hot water immersion (HWI). Significance was accepted at p ≤ 0.05. Resistance exercise induced significant temporal changes (time effect) for inflammatory, anthropometric, perceptual, and performance measures. Serum creatine kinase was reduced ( g = 0.02-0.30) after CWI ( p = 0.007), CWT ( p = 0.006), or HWI ( p < 0.001) vs. CON, whereas it increased significantly ( g = 0.50) after CWI vs. HWI. Contrast water therapy resulted in significantly higher ( g = 0.56) interleukin-6 concentrations vs. HWI. Thigh girth increased ( g = 0.06-0.16) after CWI vs. CON ( p = 0.013) and HWI ( p < 0.001) and between CWT vs. HWI ( p = 0.050). Similarly, calf girth increased ( g = 0.01-0.12) after CWI vs. CON ( p = 0.039) and CWT ( p = 0.018), and HWI vs. CON ( p = 0.041) and CWT ( p = 0.018). Subject belief in a postexercise intervention strategy was associated with HSP72 ("believer">"nonbeliever," p = 0.026), muscle soreness ("believer">"nonbeliever," p = 0.002), and interleukin-4 ("nonbeliever">"believer," p = 0.002). There were no significant treatment × time (interaction effect) pairwise comparisons. Choice of postexercise water immersion strategy (i.e., cold, contrast, or hot) combined with a belief in the efficacy of that strategy to enhance recovery or performance improves biological and perceptual markers of muscle damage and soreness. On same or subsequent days where resistance exercise bouts are performed, practitioners should consider athlete beliefs when prescribing postexercise water immersion, to reduce muscle soreness.

Intuitive eating is positively associated with indicators of physical and mental health among rural Australian adults.

INTRODUCTION: Rural Australians have comparatively higher rates of overweight and obesity, as well as some mental health issues. Intuitive eating has been shown to be positively associated with an array of physical and mental health indicators. Few studies, however, have been conducted with general populations, and none has explicitly examined intuitive eating among rural residents. OBJECTIVE: To investigate the prevalence of intuitive eating, and associations between intuitive eating and indicators of physical and mental health, among a general population of rural adults. DESIGN: Cross-sectional telephone survey of 200 randomly selected, non-metropolitan, English-speaking Australian residents aged 18 or older. FINDINGS: The prevalence of intuitive eating in the sample was 17.6%, with a higher level of intuitive eating among men than women (26.1% vs 9.1%). Bivariate associations between intuitive eating and each of the six health indicators were all positive and mostly statistically significant. Particularly strong was the correlation between intuitive eating and self-esteem for women (r = 0.53). After controlling for indication of an eating disorder and demographics, the associations between intuitive eating and the outcome variables held for body mass index (BMI), psychological distress and body esteem for men, and for BMI and self-esteem for women. Post hoc analyses found that BMI did not moderate the relationship for women between intuitive eating and self-esteem and that body esteem mediates the relationships between intuitive eating and BMI and psychological distress for men, and between intuitive eating and self-esteem for women. DISCUSSION: Consistent with most prior research, this study finds that intuitive eating is positively associated with several indicators of both physical and mental health among non-metropolitan residents in Australia. Practice of intuitive eating in this population, however, is low. These findings may help allied health professionals guide rural populations to better health, and may be a particularly effective approach for people for whom the barriers to seeking out health services are high. CONCLUSION: Intuitive eating appears to have substantial correlations with mental health indicators, and to some extent, physical health indicators, among rural Australians and therefore should be further investigated for its potential to inform public health policy targeted to similar populations.

The effects of verbal cueing for high intended movement velocity on power, neuromuscular activation, and performance.

It is widely believed that lifting heavy loads slowly, but with a conscious intention to move at high velocity, can produce resistance training (RT) adaptations indicative of rapid movements. This study investigated the effects of verbally cued high "intended" movement velocity (HIMV) during RT on neuromuscular and performance outcomes. 20 untrained volunteers (aged 24.2 ± 3.9 years) participated in 3 weeks of knee extension training. Participants were randomly allocated to receive verbal cues focusing on high intended movement velocity, HIMV, or steady and controlled movement, TRAD (traditional training). All other training variables, including actual movement velocity (30° s-1 ), remained constant. Increase in mean power output at 30° s-1 was greater for TRAD than HIMV (76% and 33%, respectively, P = 0.027). There were main effects for time (but no between-group differences) for maximal isometric force (+14%, P = 0.003), peak torque at 180° s-1 (+22%, P = 0.006), peak torque at 30° s-1 (+29%, P < 0.001), 3-repetition maximum (+20%, P < 0.001), and resting corticospinal excitability (+43%, P = 0.017). There were no differences between groups or across time for voluntary activation (P = 0.793), spinal excitability (P = 0.686), or intracortical inhibition (all P > 0.05). HIMV verbal cueing did not produce additional neurophysiological or performance benefits when compared to traditional cueing. Overall, our results demonstrated that verbal cueing did not alter the principle of velocity-specific adaptation. Cueing that increases the duration of maximal effort may be optimal for maximizing average power output at low speeds.

Impaired recovery is associated with increased injury and illness: A retrospective study of 536 female netball athletes.

Sport science and medicine practitioners are interested in the relationships between training load, injury, and illness. The extent to which training preparedness is associated with workload-related injury and illness risk is debated. Therefore, this study applied multi-level mixed effect logistic regression to investigate time-dependent (±7- and ±28-day) relationships between training preparedness (fatigue, mood, motivation, soreness, stress, sleep duration, and quality), training load, injury, and illness in 536 elite and pre-elite female netball athletes. Absolute risk (AR ± 95% CI) of sustaining an injury (0.98 ± 0.06%, n = 1122 injuries, N = 254 athletes) or illness (1.09 ± 0.10%, n = 2881, N = 432 athletes) was calculated. All training preparedness variables combined resulted in an absolute risk of 0.88%-5.88% and 0.87%-20% for injury and illness, respectively. Injury and illness had significant (P < .05) bidirectional (ie, both increased and decreased) associations with physical (soreness) and physiological (sleep duration and quality), while illness also had negative (mood, motivation) and positive (stress) associations with psychological training preparedness variables. Low sleep duration in the 48-h period prior was associated (P = .005) with increased injury risk (OR = 0.91 ± 0.03; AR = 4.00%), while "very poor" sleep quality (OR = 0.59 ± 0.02; AR = 7.83%) or extremes of too little (<5 hours, OR = 1.01 ± 0.03; AR = 3.13%-14.29%) and too much (>10 hours, OR = 1.01 ± 0.03; AR = 2.61%-10.98%) sleep had bidirectional associations (P < .001) with an increased illness risk. Changes in training preparedness variables demonstrated bidirectional associations with injury and illness. These outcomes suggest that sport science and medicine practitioners should monitor sleep, physical, and psychological recovery status, to aid early detection and intervention regarding injury and illness symptomology.

Lack of Evidence for Non-Local Muscle Fatigue and Performance Enhancement in Young Adults.

Post-activation performance enhancement (PAPE) is an improvement to voluntary muscle performance following a conditioning activity. There is evidence of fatigue resistance deficits in non-exercised muscles following unilateral fatiguing exercise of a contralateral muscle. The purpose of this study was to determine if a unilateral conditioning exercise protocol could induce PAPE in a contralateral, non-exercised muscle in young healthy adults. Thirty-two recreationally trained (n = 16) and athletically trained (n = 16) participants (16 males; age: 22.9 ± 2.03 years; height: 1.81 ± 0.06 m; weight: 82.8 ± 9.43 kg, and 16 females; age: 23.1 ± 2.80 years; height: 1.67 ± 0.07 m; weight: 66.4 ± 11.09 kg) were randomly allocated into two groups (dominant or non-dominant limb intervention). The experimental intervention, involved a conditioning exercise (4-repetitions of 5-seconds knee extension maximal voluntary isometric contractions: MVIC) with either the dominant (DOM) (n = 16) or non-dominant (ND) (n = 16) knee extensors with testing of the same (exercised) or contralateral (non-exercised) leg as well as a control (no conditioning exercise: n = 32) condition. Testing was performed before, 1-minute and 10-minutes after a high intensity, low volume, conditioning protocol (2 sets of 2x5-s MVIC). Pre- and post-testing included MVIC force and F100 (force developed in the first 100 ms: a proxy measure of rate of force development) and unilateral drop jump (DJ) height and contact time. There were no significant MVIC peak force or EMG nor DJ height or contact time interactions (intervention x limb dominance x time). The pre-test (0.50 ± 0.13) dominant leg MVIC F100 forces exceeded (p = 0.02) both post-test and post-10 min by a small magnitude 8.7% (d = 0.31). There was also a significant (p = 0.02) time x intervention leg x testing leg intervention, although it was observed that the control condition was as likely to demonstrate small to large magnitude changes as were the dominant and non-dominant legs. Following the conditioning activity, there was no significant evidence for non-local improvements (PAPE), or performance decreases.

Unilateral Quadriceps Fatigue Induces Greater Impairments of Ipsilateral versus Contralateral Elbow Flexors and Plantar Flexors Performance in Physically Active Young Adults.

Non-local muscle fatigue (NLMF) studies have examined crossover impairments of maximal voluntary force output in non-exercised, contralateral muscles as well as comparing upper and lower limb muscles. Since prior studies primarily investigated contralateral muscles, the purpose of this study was to compare NLMF effects on elbow flexors (EF) and plantar flexors (PF) force and activation (electromyography: EMG). Secondly, possible differences when testing ipsilateral or contralateral muscles with a single or repeated isometric maximum voluntary contractions (MVC) were also investigated. Twelve participants (six males: (27.3 ± 2.5 years, 186.0 ± 2.2 cm, 91.0 ± 4.1 kg; six females: 23.0 ± 1.6 years, 168.2 ± 6.7 cm, 60.0 ± 4.3 kg) attended six randomized sessions where ipsilateral or contralateral PF or EF MVC force and EMG activity (root mean square) were tested following a dominant knee extensors (KE) fatigue intervention (2×100s MVC) or equivalent rest (control). Testing involving a single MVC (5s) was completed by the ipsilateral or contralateral PF or EF prior to and immediately post-interventions. One minute after the post-intervention single MVC, a 12×5s MVCs fatigue test was completed. Two-way repeated measures ANOVAs revealed that ipsilateral EF post-fatigue force was lower (-6.6%, p = 0.04, d = 0.18) than pre-fatigue with no significant changes in the contralateral or control conditions. EF demonstrated greater fatigue indexes for the ipsilateral (9.5%, p = 0.04, d = 0.75) and contralateral (20.3%, p < 0.01, d = 1.50) EF over the PF, respectively. There were no significant differences in PF force, EMG or EF EMG post-test or during the MVCs fatigue test. The results suggest that NLMF effects are side and muscle specific where prior KE fatigue could hinder subsequent ipsilateral upper body performance and thus is an important consideration for rehabilitation, recreation and athletic programs.

Modulation of Countermovement Jump-Derived Markers of Neuromuscular Function With Concurrent vs. Single-Mode Resistance Training.

Pattison, KJ, Drinkwater, EJ, Bishop, DJ, Stepto, NK, and Fyfe, JJ. Modulation of countermovement jump-derived markers of neuromuscular function with concurrent vs. single-mode resistance training. J Strength Cond Res 34(6): 1497-1502, 2020-This study assessed changes in countermovement jump (CMJ)-derived markers of neuromuscular function with concurrent training vs. resistance training (RT) alone and determined associations between changes in CMJ parameters and other neuromuscular adaptations (e.g., maximal strength gain). Twenty-three recreationally active men performed 8 weeks of RT alone (RT group, n = 8) or combined with either high-intensity interval training cycling (HIIT + RT group, n = 8) or moderate-intensity continuous cycling (MICT + RT group, n = 7). Maximal strength and CMJ performance were assessed before (PRE), after 4 weeks of training (MID), and >72 hours (maximal strength) or >5-7 days (CMJ performance) after (POST) the training intervention. Improvements in CMJ relative peak force from both PRE to MID and PRE to POST were attenuated for both HIIT + RT (effect size [ES]: -0.44; ±90% confidence limit, ±0.51 and ES: -0.72; ±0.61, respectively) and MICT + RT (ES: -0.74; ±0.49 and ES: -1.25; ±0.63, respectively). Compared with RT alone, the change in the flight time to contraction time ratio (FT:CT) was attenuated from PRE to MID for MICT + RT (ES: -0.38; ±0.42) and from PRE to POST for both MICT + RT (ES: -0.60; ±0.55) and HIIT + RT (ES: -0.75; ±0.30). PRE to POST changes in both CMJ relative peak force and flight time:contraction time (F:C) ratio were also associated with relative 1 repetition maximum leg press strength gain (r = 0.26 and 0.19, respectively). These findings highlight the utility of CMJ testing for monitoring interference to improvements in neuromuscular function with concurrent training.

Comparison of the Hang High Pull and Loaded Jump Squat for the Development of Vertical Jump and Isometric Force-Time Characteristics.

Oranchuk, DJ, Robinson, TL, Switaj, ZJ, and Drinkwater, EJ. Comparison of the hang high pull and loaded jump squat for the development of vertical jump and isometric force-time characteristics. J Strength Cond Res 33(1): 17-24, 2019-Weightlifting movements have high skill demands and require expert coaching. Loaded jumps have a comparably lower skill demand but may be similarly effective for improving explosive performance. The purpose of this study was to compare vertical jump performance, isometric force, and rate of force development (RFD) after a 10-week intervention using the hang high pull (hang-pull) or trap-bar jump squat (jump-squat). Eighteen National Collegiate Athletic Association Division II swimmers (8 males, 10 females) with at least 1 year of resistance training experience volunteered to participate. Testing included the squat jump (SJ), countermovement jump, and the isometric midthigh pull (IMTP). Vertical ground reaction forces were analyzed to obtain jump height and relative peak power. Relative peak force, peak RFD, and relative force at 5 time bands were obtained from the IMTP. Subjects were randomly assigned to either a hang pull (n = 9) or jump-squat (n = 9) training group and completed a 10-week, volume-equated, periodized training program. Although there was a significant main effect of training for both groups, no statistically significant between-group differences were found (p ≥ 0.17) for any of the dependent variables. However, medium effect sizes in favor of the jump-squat training group were seen in SJ height (d = 0.56) and SJ peak power (d = 0.69). Loaded jumps seem equally effective as weightlifting derivatives for improving lower-body power in experienced athletes. Because loaded jumps require less skill and less coaching expertise than weightlifting, loaded jumps should be considered where coaching complex movements is difficult.

The Impact of Dry-Land Sprint Start Training on the Short Track Speed Skating Start.

Haug, WB, Drinkwater, EJ, Cicero, NJ, Barthell, JA, and Chapman, DW. The impact of dry-land sprint start training on the short track speed skating start. J Strength Cond Res 33(2): 544-548, 2019-This investigation sought to determine the effects of dry-land sprint start training on short track speed skating (STSS) start performance. Nine highly trained short track athletes completed a control period of normal STSS training followed by a 4-week training intervention. Before and after the control and intervention periods, athletes performed 3 electronically timed dry-land and on-ice 14.43 m maximal sprint start efforts. The intervention consisted of 2 sprint sessions per week consisting of 9 electronically timed 14.43 m dry-land sprint starts in addition to normal STSS training. The control period resulted in no substantial change in on-ice start performance (mean Δ: -0.01 seconds, 95% confidence limit [CL]: -0.08 to 0.05 seconds; effect size [ES]: -0.05; trivial); however, a small change was observed in dry-land start performance (mean Δ: -0.07 seconds, 95% CL: -0.13 to -0.02 seconds; ES: -0.49). After brief specific dry-land sprint start training, a small improvement was observed in both on-ice (Mean Δ: -0.07 seconds, 95% CL: -0.13 to -0.01 seconds; ES: -0.33) and dry-land (Mean Δ: -0.04 seconds, 95% CL: -0.09 to 0.00 seconds; ES: -0.29) start performance. This investigation suggests that STSS start performance can be improved through a brief dry-land sprint start training program.

Comparison Between Back Squat, Romanian Deadlift, and Barbell Hip Thrust for Leg and Hip Muscle Activities During Hip Extension.

Delgado, J, Drinkwater, EJ, Banyard, HG, Haff, GG, and Nosaka, K. Comparison between back squat, Romanian deadlift, and barbell hip thrust for leg and hip muscle activities during hip extension. J Strength Cond Res 33(10): 2595-2601, 2019-This study compared muscle activities of vastus lateralis (VL), biceps femoris (BF), and gluteus maximus (GM) during the back squat (SQ), Romanian deadlift (RDL), and barbell hip thrust (BHT) exercises performed with the same load (60 kg) and at one repetition maximum (1RM). Eight men with a minimum of 1 year's lower-body strength training experience performed the exercises in randomized order. Before each exercise, surface electromyography (EMG) was recorded during a maximal voluntary isometric contraction (MVIC) and then used to normalize to each muscle's EMG during each trial. Barbell hip thrust showed higher GM activity than the SQ (effect size [ES] = 1.39, p = 0.038) but was not significantly different from RDL (ES = 0.49, p = 0.285) at 1RM. Vastus lateralis activity at 1RM during the SQ was significantly greater than RDL (ES = 1.36, p = 0.002) and BHT (ES = 2.27, p = 0.009). Gluteus maximus activity was higher during MVIC when compared with the 60 kg load for the SQ (ES = 1.29, p = 0.002) and RDL (ES = 1.16, p = 0.006) but was similar for the BHT (ES = 0.22, p = 0.523). There were no significant differences in GM (ES = 0.35, p = 0.215) and BF activities (ES = 0.16, p = 0.791) between 1RM and MVIC for the SQ. These findings show that the RDL was equally as effective as the BHT for isolating the hip extensors, while the SQ simultaneously activated the hip and knee extensors.

Learning the Hang Power Clean: Kinetic, Kinematic, and Technical Changes in Four Weightlifting Naive Athletes.

The investment in learning required to reach benefit with weightlifting training is currently not well understood in elite athletes. The purpose of this investigation was to quantify changes in vertical jump power production and kinematic variables in hang power clean (HPC) performance during the learning process from a naive state in a multiple single-subject research design. Four elite athletes undertook HPC learning for approximately 20-30 minutes twice per week over a 169-day period. Changes in parameters of vertical power production during squat jump (SJ) and countermovement jump (CMJ) were monitored from baseline (day 0) and at 3 additional occasions. Hang power clean movement kinematics and bar path traces were monitored from day 35 and at 3 additional occasions particular to the individual's periodized training plan. Descriptive statistics were reported within athletes as mean ± SD. We observed a 14.1-35.7% (SJ) and a -14.4 to 20.5% (CMJ) gain in peak power across the 4 jump testing occasions with improvements over the first 4 weeks (SJ: 9.2-32.6%; CMJ: -2.91 to 20.79%). Changes in HPC movement kinematics and barbell path traces occurred for each athlete indicating a more rearward-directed center of pressure over the concentric phase, greater double knee bend during the transition phase, decreased maximal plantar flexion, and minimal vertical displacement of body mass with HPC learning. Considering the minimal investment of 4 weeks to achieve increases in vertical power production, the benefits of training with HPC justified the associated time costs for these 4 elite athletes.