Impaired pre-competition wellbeing measures can negatively impact running performance in developmental youth female soccer players.

This study aimed to determine the association between pre-competition perceived player wellbeing measures and subsequent relative and peak running performance of developmental youth female soccer players (n = 15, age: 16 ± 1 years). Total distance (TD), high-speed (> 3.5 m/s) (HSRD) and very high-speed (> 5.3 m/s) running (VHSRD) were expressed using 1-, 2- and 5-minute epochs and relative (per minute) calculations. Fatigue, sleep quality, upper and lower-body muscle soreness, stress, and mood wellbeing measures were collected via a self-reported questionnaire (1-5 Likert scale). Menstrual cycle phase was collected via a calendar-based countback method. Results demonstrated that reductions in stress was associated with decreased relative and peak TD in all epochs (p = 0.008-0.040), relative and peak HSRD (p = 0.006-0.039) in 2- and 5-minute epochs as well as VHSRD in 2-minute epochs (p = 0.026). For example, a one-point reduction of 'normal' to 'relaxed' is associated with a decrease of 7 m/min in peak TD for 1-minute epochs. One-point increase in fatigue (e.g., 'normal' to 'more tired than normal') displayed a decrease of 7 m/min peak TD for 2-minute (p = 0.048) and 9 m/min for 5-minute (p = 0.007) rolling epochs. Likewise, one-point increase in lower-body muscle-soreness (e.g., 'normal' to 'increase in soreness/tightness') was associated with a reduction of 6 m/min peak VHSRD for 1-minute epochs (p = 0.034). Results suggest that perceived player wellbeing can influence running performance. However, the magnitude of the change in player wellbeing should be considered in a practical sense.

The effect of compression and combined compression-tactile stimulation on lower limb somatosensory acuity.

Background: Lower limb somatosensation and proprioception are important for maintaining balance. Research has shown that compression garments or exposure to textured surfaces, can enhance somatosensation however, little is known about the effect of combined compression and texture on somatosensory acuity in the lower limb. This study aimed to assess the effects of combined compression socks with a plantar textured sole, on lower limb somatosensory acuity. Methods: Thirty participants completed a somatosensory acuity task (active movement extent discrimination apparatus; AMEDA) under three conditions: barefoot (control condition), standard knee-high compression sock (compression sock), and knee-high compression sock with internal rubber nodules situated on the sole (textured-compression sock). Somatosensory acuity was assessed between the different sock conditions for the (i) entire group, (ii) high performers, and (iii) low performers. It was hypothesized that low performers would see gains wearing either sock, but the greatest improvement would be in the textured-compression sock condition. Results: AMEDA scores were not significantly different between conditions when the entire group was analyzed (p = 0.078). The low performers showed an improvement in somatosensory acuity when wearing the compression sock (p = 0.037) and the textured compression sock (p = 0.024), when compared to barefoot, but there was no difference between the two sock conditions (p > 0.05). The high performers did not show any improvement (p > 0.05 for all). Conclusion: These findings demonstrate that additional sensory feedback may be beneficial to individuals with lower baseline somatosensory acuity but is unlikely to provide benefit for those with higher somatosensory acuity.

The Effects of a Field-Based Priming Session on Perceptual, Physiological, and Performance Markers in Female Rugby Sevens Players.

PURPOSE: This study aimed to determine the effects of a field-based priming session on perceptual, physiological, and performance responses in female rugby sevens athletes. METHODS: Thirteen highly trained female rugby sevens players (age: 20.7 [2.0] y; height: 169.3 [4.8] cm; weight: 68.8 [7.9] kg) completed either a 20-minute field-based priming session or a control condition. Perceptual, physiological, and performance variables were collected at baseline (PRE) and 5 (POST5), 30 (POST30), and 120 minutes (POST120) postintervention. Data were analyzed using Bayesian mixed effects models. RESULTS: The priming protocol had a larger increase in mental readiness (maximum a posteriori [MAP] = 20, 95% high-density intervals [HDI] = -4 to 42, probability of direction [PD]% = 95, % in region of practical equivalence [ROPE] = 9.7), physical readiness (MAP = 20.1, 95% HDI = -4.6 to 42.1, PD% = 93, % in ROPE = 10.6), and testosterone (MAP = 14.9, 95% HDI = 0.5 to 27.7, PD% = 98, % in ROPE = 5.6) than the control POST30. Cognitive performance decreased POST120 in the priming condition for congruent (MAP = 0.02, 95% HDI = -0.06 to 0.00, PD% = 95, % in ROPE = 6.4) and incongruent tasks (MAP = 0.00, 95% HDI = -0.07 to 0.00, PD% = 98, % in ROPE = 3.2) when compared with the control. CONCLUSIONS: Perceptual and physiological markers improved POST30 in the priming condition. Findings indicate that perceptual and physiological responses to priming were not coupled with performance improvements. Priming was not accompanied by perceptual, physiological, or performance improvements at POST120.

Substitute running outputs in elite youth male soccer players: less peak but greater relative running outputs.

Coaches consider substitute players to be a substantial factor in influencing the outcome of a soccer match. Substitute players are expected to make physical impact on the match by superseding the running output of the player they replaced and are a key tool for managing in-game fatigue and influencing the outcome of a game. This study investigated the physical impact and internal response of substitute players, compared to starting and full-match players. We also sought to determine if differences between substitution statuses were influenced by playing position. Players wore 15-Hz global positioning system tracking devices across 29 competition matches and were categorised according to their substitution status (full-match, starters, substitutes) and playing position (external defender, midfield, external attacker and central attacker). Peak total (TD) and high-speed running (> 5.0 m/s) distance (HSRD) were calculated using 1-, 2- and 5-minute rolling epochs. Relative running demands were reported as TD and HSRD per minute of total playing time. Substitute players performed less peak TD and HSRD in 1-, 2- and 5-minute epochs, and reported lower RPE compared to starting and full-match players. In contrast, substitutes performed greater relative HSRD per minute than starting and full-match players (p < 0.001, |d| range = 0.35-1.34). In conclusion, substitute players may have a relative physical impact but do not replicate or supersede the peak demands of full-match players. Coaches and practitioners should implement targeted warm-up interventions to enhance substitute readiness to meet the peak running demands in order to have a more effective physical impact.

Curves and kinematics: Relationship between the force-time curve and landing ability.

Anterior cruciate ligament (ACL) injuries have a significant impact on athletic performance and long-term quality of life. Force plates and qualitative screening tools are feasible and effective screening methods to identify abnormal movement quality associated with increased injury risk. Comparing qualitative assessments of landing ability with force-time curves, may detect unique differences between safe and high-risk athletic movement patterns. The aim of this study was to determine low- and high-risk landing ability from qualitive landing assessments and to examine the resulting force-time curves using functional principal component analysis (fPCA). Thirty-one healthy academy athletes (10 males and 21 females) completed double- and single-leg dominant and non-dominant jump-landing-rebound tasks. All movements were filmed in multiple-planes, and vertical ground reaction forces (vGRF) were simultaneously collected. The Landing Error Scoring System (LESS) and Single-Leg Landing Error Scoring System (SL-LESS) were used to score landing footage. From these scores, athletes were categorized into low-risk and high-risk groups for further analysis. fPCA was used to examine differences between landing quality groups force-time curves. Compared to high-risk landers, low-risk landers demonstrated significantly longer contact times across all movements. Scores from fPC1 revealed safe and high-risk landing techniques expose athletes to significantly different loading patterns during double- and single-leg dominant movements. A significant positive relationship was observed between fPC1 and LESS scores, however this relationship was not observed in both single-leg landing scores. Where possible incorporating curve analysis methods like fPCA into multi-faceted screening approaches may help practitioners uncover unique insights into athletic loading strategies.

The use of inertial measurement units to quantify forearm loading and symmetry during gymnastics vault training sessions.

The upper limbs are important in gymnastics vaulting, as the success of the flight phase is dependent on a quick and forceful push-off from the vault. This places the upper limbs under stress, which has been associated with pain and injury. This study aimed to quantify forearm segmental loading and symmetry when performing foundation to advanced-level vaulting skills during training. Twelve advanced-level artistic gymnasts (female, n = 6; male, n = 6) wore bilaterally forearm-mounted inertial measurement units while completing their vaulting sessions. The peak resultant acceleration for the leading and non-leading forearms during contact were calculated. Female gymnasts performed variations of Yurchenko vaults, while male gymnasts performed Handspring and Tsukahara vaults. Descriptive statistics (median and inter-quartile range), symmetry index scores, and total session impact load (measure of cumulative loading) were calculated between the lead and non-lead forearms. High asymmetrical loading was identified for some Yurchenko, Handspring, and Tsukahara vaults, with large variations identified between gymnasts. Some gymnasts experienced greater loading at their lead forearm, while others experienced greater loading at their non-lead forearm. Results indicate that limb loading patterns in advanced gymnastics are highly individualised, indicating that individual analysis is needed to identify gymnasts (or limbs) at an increased risk for overuse injury.

Do conditioning focused various-sided training games prepare elite youth male soccer players for the demands of competition?

Relative metrics (i.e. distance covered per minute of match time) are regularly used to quantify soccer player movement demands. However, limited literature is available concerning the peak player demands during training. This study aimed to compare the relative and peak demands of conditioning-focused various-sided training games (VSG) to competition matches in elite youth male soccer players according to playing position. Data from twenty-nine competition matches (national) and twenty-two VSGs (small, medium, and large) were collected for twenty-three elite under-17 soccer players using 15-Hz portable global positioning system tracking devices (GPSports, Canberra, Australia). Relative player movements were reported as total distance (TD) and high-speed running distance (HSRD) (> 5.0 m/s) per minute of total playing time. Peak player movements were calculated using a 1-minute rolling epoch length, reported as the maximum TD and HSRD. Linear mixed models demonstrated interactions between VSG type and player position for relative TD (p < 0.001) and HSRD (p < 0.001), and peak TD (p = 0.010) and HSRD (p = 0.003). The relative TD of VSGs were greater than match-play for all player positions. However, only Central Defenders demonstrated similar HSRD in MSGs and LSGs compared to match-play when analysed using relative calculations. External Attackers also replicated match-play relative HSRD demands in LSGs. No VSG type was found to replicate or supersede the peak player movements of match-play across any playing position. Consequently, VSGs should be supplemented with high-speed running training to prepare players for the peak running requirements of match-play.

Australian University Nursing and Allied Health Students' and Staff Physical Activity Promotion Preparedness and Knowledge: A Pre-Post Study Using an Educational Intervention.

The promotion of physical activity (PA) by health professionals is a key strategy to increase PA levels in the population. In this study, we investigated PA promotion, preparedness, and knowledge among university nursing and allied health students and staff, as well as PA resource usage within curricula, before and after an educational intervention. Students and staff from 13 health disciplines at one Australian university were invited to complete an online survey, and a curriculum audits were conducted before and after PA teaching resources were promoted by academic PA champions (n = 14). A total of 299 students and 43 staff responded to the survey pre-intervention, and 363 and 32 responded to the post-intervention, respectively. PA promotion role perception (≥93%) and confidence to provide general PA advice (≥70%) were high throughout the study. Knowledge of PA guidelines was poor (3−10%). Students of physiotherapy, sport and exercise science, as well as more active students, were more likely to be aware of the PA guidelines (p < 0.05). Over 12 months, PA promotion preparedness and knowledge did not change significantly, nor was there a change in the amount of PA content delivered, despite a significant increase in the use of the teaching resources across a number of disciplines (p = 0.007). Future research should be carried out to investigate the implementation of the resources over time and to develop additional strategies for PA promotion and education scaffolded across curricula.

A Multidisciplinary Approach to Game Day Preparation for Team Sports: A Delphi Study With Expert Consensus.

ABSTRACT: Mason, BRJ, Pumpa, KL, McKune, AJ, Gill, ND, and Ball, NB. A multidisciplinary approach to game day preparation for team sports: A Delphi study with expert consensus. J Strength Cond Res 36(5): 1345-1352, 2022-The aim of this study was to identify game day preparation strategies used by performance staff to improve team sport performance and to determine consensus regarding the application and importance of these strategies. Twenty-five performance staff working in high performance or professional team sports participated in this Delphi study, which implemented 3 survey rounds. The first round sought responses to open-ended questions relating to the use of game day preparation strategies. These responses were developed into statements and recirculated (round-2 survey), with subjects asked to rate their level of agreement with each statement. The third and final survey presented revised versions of statements that did not reach a consensus in the previous round, along with new statements derived from subject responses. A thematic analysis of the open-ended responses in the first survey identified 5 key themes relating to game day preparation strategies: "exercise," "nutrition," "psychological," "technical and tactical," and "other." The round-2 survey included 38 statements across the 5 themes, with 22 reaching the consensus threshold (≥75%) for agreement. The remaining 16 statements did not reach consensus. The final survey included 18 statements (16 revised and 2 new) with 12 reaching the consensus threshold for agreement. Key preparation strategies identified in this study include structured and progressive warm-ups, strength and power-based priming sessions, individualized nutrition plans, and precooling in hot conditions. Performance staff working in similar environments should consider adopting these strategies to improve athlete or team performance.

Measurement bias in estimates of system power during a vertical jump.

This investigation sought to quantify the level of measurement agreement in system force, velocity and power values derived across three commonly applied assessment techniques during a countermovement jump (CMJ). Twenty-five male national representative athletes completed three CMJs under unloaded (0%1RM) and loaded (40%1RM) jump conditions. Associated values of force, velocity and power were captured simultaneously from either a linear optical encoder (LOE) or force plate (FP) and then compared to the gold-standard reference values derived from a combined force plate and three-dimensional motion capture system (FPMC). The LOE significantly (p < 0.001) overestimated and failed to meet the minimum level of relatedness (<0.80) for measures of peak velocity, peak force, peak power and mean power across both conditions compared to the FPMC reference values. A reduction in measurement dispersion and bias was, however, evident during the loaded condition. The FP significantly (p < 0.05) underestimated mean and peak power across both conditions, yet measurement bias and dispersion remained consistent. These findings highlight a disparity in measurement agreement in force, velocity and power values across alternative assessment techniques and loads. Such variance in measurement agreement will uniquely alter derived force-velocity profiles, and thus the prescription of training loads to maximise system power during unrestricted CMJs.

Changes in Loaded Countermovement Jumps During Precompetition and Competition Training Mesocycles in Elite Rowers.

ABSTRACT: Everett, KLA, Chapman, DW, Mitchell, JA, and Ball, N. Changes in loaded countermovement jumps during precompetition and competition training mesocycles in elite rowers. J Strength Cond Res 36(9): 2622-2627, 2022-To assess changes in velocity, displacement, and power as an indicator of neuromuscular fatigue (NMF) within and between precompetition and competition mesocycles in elite male rowers using loaded countermovement jumps (CMJs). Twenty highly trained rowers completed regular training (on-water rowing, rowing ergometer, and resistance training sessions) in 2 consecutive mesocycles. Athletes completed a single set of 6 loaded (20 kg) CMJs in the first and final week of each mesocycle. Countermovement jumps were assessed for jump height (JH), eccentric displacement, mean velocity (MV), eccentric MV (EMV), and mean power. Changes between time points were reported as Cohen's d effect sizes (95% confidence interval [CI]). The magnitude of the differences was also considered based on their relative strength levels using a linear mixed model. Within the precompetition mesocycle, trivial-to-small reductions for all variables (0.5-4.1%) were observed. During the competition mesocycle, trivial-to-small increases were shown for EMV (1.4%) and eccentric displacement (2.0%) with no change in JH and small reductions in MV (0.5%) and mean power (2.8%). No differences between the precompetition and competition mesocycles were shown. Only mean power showed a significant reduction in weaker athletes (3.2%) compared with stronger athletes (2.3%). Training completed during a precompetition and competitive mesocycle did not result in significant decreases in athlete's loaded CMJ performance, indicating that NMF was minimized. Alternatively, use of a loaded CMJ may not be sensitive enough to observe NMF in elite rowers during the mesocycle immediately leading into and during a competition mesocycle.

Effects of Westbound Trans-meridian Travel on Countermovement Jump Performance in International-Level Rowers.

ABSTRACT: Everett, KLA, Chapman, DW, Mitchell, JA, and Ball, N. Effects of westbound trans-meridian travel on countermovement jump performance in international-level rowers. J Strength Cond Res 36(7): 1961-1965, 2022-International long-haul air travel is a necessity for many athletes as part of their training or competition schedules. However, long-haul travel is also associated with impaired neuromuscular function. An athlete's lower body neuromuscular status is frequently assessed and monitored using countermovement jump (CMJ). This study assessed the impact of westbound trans-meridian travel on changes in CMJ performance in highly trained aerobic athletes. Highly trained male rowers (n = 21, 23.7 ± 1.4 years, 1.91 ± 0.07 m, 86.9 ± 9.9 kg) undertook a westbound flight incurring 22 hours of flight time with 30 hours of total travel time across 9 time zones. Athletes completed a single set of 6 loaded CMJ repetitions before and after travel with performance measured using a digital optical encoder attached to a 20 kg barbell. Each CMJ repetition was assessed for mean concentric velocity, jump height (JH), eccentric displacement, JH:dip ratio, mean power, and mean eccentric velocity, with comparisons made between mean set changes before and after travel. Changes were compared using a one tail paired t-test and characterized using Cohen's d (95% confidence interval) effect sizes. Significance was accepted at p ≤ 0.05. Small-to-moderate changes were observed in all variables following westbound travel. These changes may be because of retention of high training loads before travel resulting in the athletes being in a fatigued state, whereas travel time worked as a forced recovery period. Reductions in CMJ performance are likely following westbound travel, however, may be affected by training fatigue before travel that may confound CMJ performance as a monitoring metric.

What did the ankle say to the knee? Estimating knee dynamics during landing - A systematic review and meta-analysis.

BACKGROUND: Landing-based measures of the knee are often used to assess risk of anterior cruciate ligament (ACL) injury and inform prevention strategies. There is less understanding of the ankle's influence on knee measures during landing. OBJECTIVE: 1. Examine interactions of dynamic ankle measures alongside various subject and task characteristics on knee dynamics in vertical landing and 2. Determine whether ankle measures alone can estimate dynamic knee measures associated with ACL injury risk. DESIGN: Systematic review and meta-analysis. METHODS: Electronic databases Medline, EMBASE, CINAHL, Web of Science and Cochrane were screened for studies that included measurement of initial contact angles and internal joint moments of both the ankle and knee during landing in uninjured individuals. RESULTS: 28 studies were included for analysis. Using 1144 landing trials from 859 individuals, RRelief F algorithm ranked dynamic ankle measures more important than landing task and subject characteristics in estimating knee dynamics. An adaptive boosting model using four dynamic ankle measures accurately estimated knee extension (R2 = 0.738, RMSE = 3.65) and knee abduction (R2 = 0.999, RMSE = 0.06) at initial contact and peak knee extension moment (R2 = 0.988, RMSE = 0.13) and peak knee adduction moment (R2 = 1, RMSE = 0.00). CONCLUSIONS: Dynamic ankle measures can accurately estimate initial contact angles and peak moments of the knee in vertical landing, regardless of landing task or individual subject characteristics. This study provides a theoretical basis for the importance of the ankle in ACL injury prevention.

Morning resistance exercise and cricket-specific repeated sprinting each improve indices of afternoon physical and cognitive performance in professional male cricketers.

OBJECTIVES: To compare two modes (general and cricket-specific) of morning priming exercise on afternoon physical and cognitive performance, and subjective readiness to perform in professional male cricketers. DESIGN: Randomised, crossover, counterbalanced. METHODS: On three occasions, 16 professional men's cricketers completed afternoon tests of countermovement jump height, cricket-specific sprint performance (running between the wickets, two runs), cognitive function (Stroop test, time taken), and subjective readiness to perform. Control (CON; passive rest), lower-body resistance exercise priming (LIFT; trap bar deadlifts, 6 × 4 repetitions up to 85% of one repetition maximum), or cricket-specific running priming (RUN; 6 × 35.36 m sprints including a 180° change of direction) interventions were implemented 5.5 h before testing. RESULTS: Afternoon sprint times were faster in RUN (-0.04 s, p = 0.013) and LIFT (-0.07 s, p < 0.001) versus CON, and faster in LIFT than RUN (-0.03 s, p = 0.032). Jump height (+1.1 cm, p = 0.021) and cognitive function (-3.83 s, p = 0.003) were greater in LIFT than CON, whilst RUN outperformed CON for cognition (-2.52 s, p = 0.023). Although perceived readiness was not influenced by trial (p > 0.05), players reported favourable responses on the "aggression" subscale in LIFT relative to CON (+1 arbitrary unit, p = 0.022). CONCLUSIONS: Both general (lower-body resistance exercise) and cricket-specific (simulated running between wickets) morning priming are effective match-day strategies to improve afternoon markers of physical and cognitive performance in professional men's cricketers. Practitioners may thus be afforded flexibility in situations where resistance exercise is not feasible on the morning of a match.

Identifying problems that female soldiers experience with current-issue body armour.

Despite female soldiers representing a growing user population, military body armour systems are currently better suited to the anthropometric dimensions of male soldiers. The aim of this study was to explore issues that female soldiers experience with current Australian Defence Force (ADF)-issue body armour. Following a sequential exploratory design, an initial questionnaire was completed by 97 Australian female soldiers. Subsequently, 33 Australian female soldiers participated in one of three focus groups. Descriptive statistics of questionnaire data considered alongside thematic analysis of focus group transcripts revealed problems with the design (fit, form and function) of current ADF-issue body armour, as well as problems with the issuance and education surrounding use of the system. It is recommended that anthropometric data of female soldiers be better incorporated into future body armour designs, that these data inform processes surrounding both acquisition and issuance of body armour and that training protocols for body armour use be reviewed.

Push-Ups are Able to Predict the Bench Press 1-RM and Constitute an Alternative for Measuring Maximum Upper Body Strength Based on Load-Velocity Relationships.

The aims of this study were firstly to compare the similarity in upper-body muscle activation between the bench press and push-up at similar loads, and secondly to establish a 1-RM prediction equation between the two exercises based upon the load-velocity relationship. Twenty resistance-trained male athletes (age 22.5 ± 5.24 years, body mass 83.7 ± 10.7 kg, body height 1.80 ± 0.06 m) performed push-ups and bench presses with four different loads. Push-ups were performed without a weight vest and with a 10-20-30 kg weight vest. Bench presses were performed at 50-80% of athletes' assumed 1 repetition max (1-RM) in 10 kg steps, while a linear encoder measured performance during the exercises. A load-velocity relationship was established as a product of the load and velocity for the push-up and bench press per participant and the equation was used to establish a predicted 1-RM. Mean muscle activation of eight upper body muscles was recorded for each exercise and each load. The main findings of this study demonstrate an extremely large association between the predicted 1-RM loads performed with the push-up and bench press (r = 0.93) in experienced resistance trained men. Furthermore, most muscles showed similar activations between the two exercises with the different loads except the deltoid and biceps brachii muscles. It may be concluded that it is possible to predict a cross-over 1-RM between the two exercises based upon the load-velocity relationship in each exercise, and that training push-ups largely targets the same muscles as the bench press except the deltoid and biceps muscles. For coaches and athletes, the use of this method is a low cost and time-effective alternative for standard 1-RM bench press testing to predict maximal upper body strength.

The Use of Acute Exercise Interventions as Game Day Priming Strategies to Improve Physical Performance and Athlete Readiness in Team-Sport Athletes: A Systematic Review.

BACKGROUND: The use of exercise as a priming strategy to enhance sport performance is becoming increasingly popular in professional sports and as an area of research interest. Early research suggests that the acute physiological responses to exercise can positively influence performance for up to 48 h. There is yet to be a comprehensive review of exercise strategies which could be implemented specifically on the day of competition. OBJECTIVES: The aim of this systematic review was to provide a synthesis of research investigating acute exercise interventions as game day priming strategies for team-sport athletes to improve physical performance and athlete readiness when implemented in the 1-12 h prior to competition. METHODS: A literature search of SPORTDiscus, PubMed and Cochrane Central Register for Controlled Trials was conducted. A total of 6428 studies were retrieved and assessed against the following inclusion criteria: (1) randomised controlled trials and non-randomised comparative studies with reported pre-post intervention outcomes; (2) exercise interventions were applied 1-12 h prior to the assessment of outcome measures. Studies were excluded if they used nutrition, supplementation, pre-heating, pre-cooling, stretching, massage or vibration training as the priming strategies, or if interventions were performed at altitude or in hypoxic environments. Studies were assessed for methodological quality at the study level using the Physiotherapy Evidence Database (PEDro) scale. RESULTS: Twenty-nine studies satisfied the eligibility criteria and were included in this review. Studies were categorised as resistance training; cycling; running; and other strategies. Resistance training using heavy loads at low volumes increased strength and power measures following a 4-6 h recovery, with limited improvements observed following shorter (1-3 h) and longer (6-12 h) recovery periods. Running-based sprint priming led to improvements in subsequent sprint and repeat sprint performance following a 5-6 h recovery, whereas cycling improved counter-movement jump height in a single study only. No significant differences were reported in any performance measures following endurance-based running or cycling strategies. Physiological markers, such a hormone and blood lactate responses, showed mixed results between studies. CONCLUSIONS: High-intensity low-volume resistance training leads to a greater physiological and performance response than high-volume resistance training. Maximal running sprints may be more effective than maximal cycling sprints due to an increased physiological demand; however, loading protocols must also be considered in conjunction with exercise volume and movement specificity to achieve a beneficial response for subsequent performance. There is limited evidence to suggest endurance cycling or running exercise is beneficial as a priming strategy.

The Effect of Acute Body Unloading on Somatosensory Performance, Motor Activation, and Visuomotor Tasks.

Evaluating countermeasures designed to reduce the impact of microgravity exposure on astronaut performance requires the development of effective methods of assessing changes to sensorimotor function in 1g analog systems. In this study, somatosensation at the ankle and fingers, lower leg muscle activity and visuomotor control were assessed using a full body loading and acute unloading model to simulate microgravity. It was hypothesized that the function of the hands and eyes are not constrained to 'weight bearing' postures for optimal function and would not differ between the loaded and acute unloaded conditions, whereas lower leg muscle activity and ankle somatosensation would be reduced in the acute unloaded condition. Somatosensation was recorded using the Active Movement Extent Discrimination Apparatus (AMEDA) protocol where participants were required to make an absolute judgment of joint position sense. A score closer to 1.0 demonstrates higher accuracy. Lower leg muscle activity was recorded using electromyography of major lower leg musculature to observe peak muscle activity and duration of contraction. The King Devick infrared eye tracking test was used to asses visuomotor control by monitoring saccade velocity and fixation time. In acute unloading, it was found that ankle somatosensation had decreased accuracy (loaded 0.68, unloaded 0.66, p = 0.045) while finger somatosensation improved (loaded 0.77, unloaded 0.79, p = 0.006). When acutely unloaded, peak lower leg muscle activation reduced ( > 27%) and total contraction time increased (2.02 × longer) compared to loading. Visuomotor assessment results did not vary between the loaded and acute unloaded postures, however the underlying techniques used by the participant to complete the task (saccade velocity and fixations time) did increase in acute unloaded conditions. SIGNIFICANCE: This research provides an insight to how to the human body responds immediately to acute changes of gravitational load direction. It provides insight to the acute affects' astronauts may encounter when in microgravity.

Effects of digital filtering on peak acceleration and force measurements for artistic gymnastics skills.

Low-pass filters are ideal when filtering human movements, however the effectiveness of such filters relies on the correct selection of the cut-off frequency. The aim of this study was to determine the most appropriate filter cut-off for acceleration- and force-time data when measuring peak resultant acceleration (PRA) and ground reaction force (PRGRF) during gymnastics landings. Sixteen gymnasts executed backward handsprings and backward somersault landings onto a matted force plate while wearing four inertial measurement units (IMUs). Acceleration- and force-time data were filtered using a fourth-order Butterworth filter at different cut-off frequencies ranging from raw through to 250 Hz. Residual analysis plots were produced, and the PRGRF and PRA for all IMUs were calculated for each participant and skill at all cut-off frequencies. Descriptive statistics, model II linear regressions and Bland-Altman plots were conducted. Results indicated that a minimum 85 Hz cut-off is optimal. High cut-off frequencies (>80 Hz) showed good linear relationships and had minimal mean bias compared with raw values, indicating that either filtered (above ~85 Hz) or raw signals can be used. It is suggested that for applied sports settings no filtering is needed, however a minimum cut-off of 85 Hz should be implemented for research purposes.

Validity and Reliability of Kinematics Measured with PUSH Band vs. Linear Encoder in Bench Press and Push-Ups.

BACKGROUND: The aim of this study was to compare the validity and reliability of a PUSH band device with a linear encoder to measure movement velocity with different loads during the push-up and bench press exercises. METHODS: Twenty resistance-trained athletes performed push-up and bench press exercises with four different loads: without weight vest, 10-20-30 kg weight vest, bench press: 50-82% of their assumed 1 repetition maximum (1 RM) in steps of 10 kg. A linear encoder (Musclelab) and the PUSH band measured mean and peak velocity during both exercises. Several statistical analyses were used to investigate the validity and reliability of the PUSH band with the linear encoder. RESULTS: The main findings of this study demonstrated only moderate associations between the PUSH band and linear encoder for mean velocity (r = 0.62, 0.70) and peak velocity (r = 0.46, 0.49) for both exercises. Furthermore, a good level of agreement (peak velocity: ICC = 0.60, 0.64; mean velocity: ICC = 0.77, 0.78) was observed between the two measurement devices. However, a significant bias was found with lower velocity values measured with the PUSH band in both exercises. In the push-up, both the linear encoder and PUSH band were deemed very reliable (ICC > 0.98; the coefficient of variation (CV): 5.9-7.3%). Bench press reliability decreased for the PUSH band (ICC < 0.95), and the coefficient of variance increased to (12.8-13.3%) for the velocity measures. Calculated 1 RM with the two devices was the same for the push-up, while in bench press the PUSH band under-estimated the 1 RM by 14 kg compared to the linear encoder. CONCLUSIONS: It was concluded that the PUSH band will show decreased reliability from velocity measures in a bench press exercise and underestimate load-velocity based 1 RM predictions. For training, the PUSH band can be used during push-ups, however caution is suggested when using the device for the purposes of feedback in bench press at increasing loads.