Purpose: To establish the reliability of various measures obtained during single and repeated countermovement jump (CMJ) performance in an elite athlete population.Methods: Two studies, each involving 15 elite Australian Rules Football (ARF) players were conducted where subjects performed two days, separated by one week, of AM and PM trials of either a single (CMJ1) or 5 repeated CMJ (CMJ5). Each trial was conducted on a portable force-plate. The intraday, interday, and overall typical error (TE) and coefficient of variation (CV%) were calculated for numerous variables in each jump type.Results: A number of CMJ1 and CMJ5 variables displayed high intraday, interday, and overall reliability. In the CMJ1 condition, mean force (CV 1.08%) was the most reliable variable. In the CMJ5, fight time and relative mean force displayed the highest repeatability with CV of 1.88% and 1.57% respectively. CMJ1Mean force was the only variable with an overall TE < smallest worthwhile change (SWC).Conclusion: Selected variables obtained during CMJ1 and CMJ5 performance can be used to assess the impact of both acute and chronic training and competition. Variables derived from the CMJ5 may respond differently than their CMJ1 counterparts and should provide insights into differential mechanisms of response and adaptation.

Introduction: The purpose of this study was to examine the changes in neuromuscular, perceptual and hormonal measures following professional rugby league matches during different length between-match microcycles.Methods: Twelve professional rugby league players from the same team were assessed for changes in countermovement jump (CMJ) performance (fight time and relative power), perceptual responses (fatigue, well-being and muscle soreness) and salivary hormone (testosterone [T] and cortisol [C]) levels during 5, 7 and 9 d between-match training microcycles. All training was prescribed by the club coaches and was monitored using the session-RPE method.Results: Lower mean daily training load was completed on the 5 d compared with the 7 and 9 d microcycles. CMJ fight time and relative power, perception of fatigue, overall well-being and muscle soreness were signifcantly reduced in the 48 h following the match in each microcycle (P < .05). Most CMJ variables returned to near baseline values following 4 d in each microcycle. Countermovement jump relative power was lower in the 7 d microcycle in comparison with the 9 d microcycle (P < .05). There was increased fatigue at 48 h in the 7 and 9 d microcycles (P < .05) but had returned to baseline in the 5 d microcycle. Salivary T and C did not change in response to the match.Discussion: Neuromuscular performance and perception of fatigue are reduced for at least 48 h following a rugby league match but can be recovered to baseline levels within 4 d. These fndings show that with appropriate training, it is possible to recover neuromuscular and perceptual measures within 4 d after a rugby league match.

Purpose: To assess the validity and reliability of distance data measured by global positioning system (GPS) units sampling at 1 and 5 Hz during movement patterns common to team sports.Methods: Twenty elite Australian Football players each wearing two GPS devices (MinimaxX, Catapult, Australia) completed straight line movements (10, 20, 40 m) at various speeds (walk, jog, stride, sprint), changes of direction (COD) courses of two different frequencies (gradual and tight), and a team sport running simulation circuit. Position and speed data were collected by the GPS devices at 1 and 5 Hz. Distance validity was assessed using the standard error of the estimate (±90% confidence intervals [CI]). Reliability was estimated using typical error (TE) ± 90% CI (expressed as coefficient of variation [CV]).Results: Measurement accuracy decreased as speed of locomotion increased in both straight line and the COD courses. Difference between criterion and GPS measured distance ranged from 9.0% to 32.4%. A higher sampling rate improved validity regardless of distance and locomotion in the straight line, COD and simulated running circuit trials. The reliability improved as distance traveled increased but decreased as speed increased. Total distance over the simulated running circuit exhibited the lowest variation (CV 3.6%) while sprinting over 10 m demonstrated the highest (CV 77.2% at 1 Hz).Conclusion: Current GPS systems maybe limited for assessment of short, high speed straight line running and efforts involving change of direction. An increased sample rate improves validity and reliability of GPS devices.

Purpose: To examine the acute and short-term responses of variables obtained during a single countermovement jump (CMJ1); repeated countermovement jump involving 5 consecutive efforts without a pause (CMJ5); and cortisol, testosterone, and testos-terone-to-cortisol ratio (T:C) to an elite Australian Rules Football (ARF) match with a view to determining which variables may be most useful for ongoing monitoring.Methods: Twenty-two elite ARF players participating in a preseason cup match performed a CMJ1 and a CMJ5 and provided saliva samples 48 h before the match (48pre), prematch (Pre), postmatch, 24 h post (24post), 72 h post (72post), 96 h post (96post), and 120 h post (120post). The magnitude of change in variables at each time point compared with Pre and 48pre was analyzed using the effect size (ES) statistic.Results: A substantial decrement in the pre- to postmatch comparison occurred in the ratio of CMJ1 Flight time:Contraction time (ES −0.65 ± 0.28). Cortisol (ES 2.34 ± 1.06) and T:C (ES −0.52 ± 0.42) displayed large pre- to postmatch changes. The response of countermovement variables at 24post and beyond compared with pre-match and 48pre was varied, with only CMJ1 Flight time:Contraction time displaying a substantial decrease (ES −0.32 ± 0.26) postmatch compared with 48pre. Cortisol displayed a clear pattern of response with substantial elevations up to 24post compared with Pre and 48pre.Conclusion: CMJ1 Flight time:Contraction time appears to be the most useful variable for monitoring neuromuscular status in elite ARF players due to its substantial change compared with 48pre and prematch. Monitoring cortisol, due to its predictable pattern of response, may provide a useful measure of hormonal status.

Purpose: To examine the difference in distance measured by two global positioning system (GPS) units of the same model worn by the same player while performing movements common to team sports.Methods: Twenty elite Australian football players completed two trials of the straight line movement (10, 20, 40 m) at four speeds (walk, jog, stride, sprint), two trials of the changes of direction (COD) courses of two different frequencies (gradual and tight), and five trials of a team sport running simulation circuit. To assess inter-unit variability for total and high intensity running (HIR) distance measured in matches, data from eight field players were collected in three Australian Hockey League (AHL) matches during the 2009 season. Each subject wore two GPS devices (MinimaxX v2.5, Catapult, Australia) that collected position data at 5 Hz for each movement and match trial. The percentage difference ±90% confidence interval (CI) was used to determine differences between units.Results: Differences (±90% CI) between the units ranged from 9.9 ± 4.7% to 11.9 ± 19.5% for straight line running movements and from 9.5 ± 7.2% to 10.7 ± 7.9% in the COD courses. Similar results were exhibited in the team sport circuit (11.1 ± 4.2%). Total distance (10.3 ± 6.2%) and HIR distance (10.3 ± 15.6) measured during the match play displayed similar variability.Conclusion: It is recommended that players wear the same GPS unit for each exercise session to reduce measurement error. The level of between-unit measurement error should be considered when comparing results from players wearing different GPS units.

Franchini, E, Cormack, S, and Takito, MY. Effects of high-intensity interval training on Olympic combat sports athletes' performance and physiological adaptation: A systematic review. J Strength Cond Res 33(1): 242–252, 2019—Combat sports represent around 25% of all Olympic medals disputed, and the success in these sports are determined by technical-tactical excellence and supported by physiological and psychological development. Although the training in combat sports is intermittent training by nature, some researchers have started to focus their attention on the effects of complementary high-intensity interval training (HIIT)-coupled standard combat sports-specific training on morphological, physiological, and performance adaptations. Thus, in this systematic review, we aimed to verify the effects of this type of training on these variables. A total of 117 articles in the electronic databases Pubmed, Scopus, and Web of Science were retrieved, and 9 studies remained in the present systematic review. A total of 228 athletes (138 judo athletes, 40 taekwondo athletes, 18 boxers, 17 karate athletes, and 15 wrestlers) were investigated in these 9 studies (5 with judo athletes, 1 with boxers, 1 with karate athletes, 1 with wrestlers, and 1 with taekwondo athletes). The HIIT protocols investigated did not generate any change in body fat percentage or body mass but generally resulted in increases in JOURNAL/jscr/04.03/00124278-201901000-00029/29FFU1/v/2023-08-19T002812Z/r/image-tiff max or JOURNAL/jscr/04.03/00124278-201901000-00029/29FFU1/v/2023-08-19T002812Z/r/image-tiff peak, varying from 4.4 to 23.0%. However, the most observed benefit of HIIT protocols was an increase in anaerobic fitness, represented by improvements in anaerobic power and capacity.