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Assessment of player's postural control following a lower limb injury is of interest to sports medicine practitioners due to its fundamental role in daily tasks and sporting activities. The aim was to longitudinally monitor professional rugby union players' postural control during each phase of the rehabilitation program (acute, middle, and late) following a lower limb injury. Seven male rugby union players (height 1.80 [0.02] m; mass 100.3 [11.4] kg; age 24 [4] y) sustained a time loss, noncontact lower limb injury. Static postural control was assessed via sway path (in meters), and dynamic postural control was assessed via vertical postural stability index. Group differences (P <.05) were reported across the acute, middle, and late phase. Smaller magnitudes of sway path were observed for eyes-open sway path, and for the middle and late phase smaller magnitudes of vertical postural stability index (P <.05) at the end session compared with first session. Whereas larger magnitudes of vertical postural stability index were found between baseline and the last session (P <.05). Large interindividual and intraindividual variation was apparent across the 3 phases of rehabilitation. Postural control improvements were identified during rehabilitation. However, postural control did not return to baseline, with altered kinetics throughout each rehabilitation phase. [ABSTRACT FROM AUTHOR]

General and local muscular fatigue is postulated to negatively alter lower limb biomechanics; however, few prospective studies have been done to examine the effect of fatigue on tuck-jump performance. The tuck-jump assessment (TJA) is a criteria-based visual screening tool designed to identify neuromuscular deficits associated with anterior cruciate ligament (ACL) injury. Use of kinetics during the TJA after an intense sport-specific fatigue protocol may identify fatigue-induced neuromuscular deficits associated with ACL injury risk. To examine the effects of a sport-specific fatigue protocol on visually evidenced (2-dimensional) technical performance of repeated tuck jumps and lower limb kinetic stabilization. Cross-sectional study. Laboratory. Twelve female netball athletes (age = 20.8 ± 2.6 years, height = 170.0 ± 0.04 cm, mass = 67.5 ± 7.4 kg). Participants performed 1 set of a TJA before and after a sport-specific fatigue protocol. Paired t tests and effect sizes were used to evaluate differences and the magnitude of differences in TJA scoring criterion, kinetics, and kinetic stabilization prefatigue to postfatigue. A small increase was observed for vertical relative lower extremity stiffness postfatigue (P =.005; Hedges g = 0.45). Peak center-of-mass displacement, time of jump cycle, ground contact time, flight time, jump height, and vertical net impulse decreased with small to moderate effect sizes (P <.01; Hedges g range, 0.41–0.74). No differences were observed for TJA composite scores, peak vertical ground reaction force, and stabilization indices of kinetic variables after the fatigue protocol (P >.05). Kinetic analysis of repeated tuck jumps after a fatigue protocol identified an altered jumping strategy, which was not identifiable via visual 2-dimensional assessment. However, based on kinetic measures, fatigue induces a stiffer jumping strategy, and practitioners should consider assessing load attenuation strategies that may not be visually evident when evaluating ACL-injury risk factors in athletes who are fatigued. [ABSTRACT FROM AUTHOR]

An examination of team-level and player-specific injury incidence in Rugby Union, using different match exposure calculations, Match time-loss injuries and match exposure using Global Positioning Systems (GPS) was collected across three seasons (2016/17–2018/19). Team-level and player-specific injury incidence were calculated using standard match length and GPS exposure. The probability of one or two or more injuries was calculated using the Poisson probability. A total of 487 injuries were sustained by 111 players. Team-level injury incidence across three seasons using standard match length was lower than the injury incidence using GPS (59.5 vs 95.7 injuries/1000 match hours, respectively). More than 84% of players fell outside the 95% confidence intervals for the team-level injury incidence each season. When exposed to a lower number of match hours, at the same incidence the probability of only one injury was higher. When exposed to a higher number of match hours, at the same incidence the probability of sustaining two or more injuries was higher. The standard match length underestimates the team-level injury incidence if the entire player cohort has not provided consent. In addition, team-level injury incidence is a poor representation of the underlying injury incidence of players. [ABSTRACT FROM AUTHOR]

This review discusses female‐specific health considerations in injury and illness surveillance and provides rugby‐specific recommendations for future surveillance. Identifying priority injury and illness problems by determining those problems with the highest rates within women's rugby may highlight different priorities than sex comparisons between men's and women's rugby. Whilst sports exposure is the primary risk for health problems in sports injury and illness surveillance, female athletes have health domains that should also be considered. Alongside female athlete health domains, studies investigating rugby injuries and illnesses highlight the need to broaden the health problem definition typically used in rugby injury and illness surveillance. Using a non‐time‐loss health problem definition, recording female‐specific population characteristics, embedding female athlete health domains and having up‐to‐date injury and illness coding systems should be prioritized within surveillance systems to begin to shed light on potential interactions between sports exposure, health domains and, injuries and illnesses. We call for a collaborative approach across women's rugby to facilitate large injury and illness datasets to be generated and enable granular level categorization and analysis, which may be necessary for certain female athlete health domains. Applying these recommendations will ensure injury and illness surveillance systems improve risk identification and better inform injury and illness prevention strategies in women's rugby. [ABSTRACT FROM AUTHOR]

Context: Kinetic profiles of athletes performing the tuck jump assessment (TJA) are unknown and may provide insight into the risk of anterior cruciate ligament injury. Design: The purpose of this study was to (1) analyze vertical kinetics of the TJA and (2) determine the stabilization of the kinetics across successive jumping cycles. Methods: Twenty-five healthy female athletes (age = 22.0 [4.6] y; height = 1.69 [0.07] m; body mass = 69.3 [10.3] kg) completed one trial of repeated tuck jumps on a force plate for 10 seconds. Results: Vertical ground reaction force data were used to calculate the following variables across all jump cycles: time of jump cycle (0.65 [0.04] s), ground contact time (0.22 [0.03] s), flight time (0.43 [0.04] s), duty factor (0.34 [0.05]), jump height (0.23 [0.04] m), peak vertical force (5.52 [0.91] body weight [BW]), peak center of mass displacement (0.15 [0.02] m), vertical leg stiffness (27.09 [7.06] BW·m−1), vertical average loading rate (105.94 [28.43] BW·s−1), vertical instantaneous loading rate (140.90 [28.49] BW·s−1), and net impulse (0.43 [0.03] BW·s). A sequential averaging technique indicated a minimum of 11 jumps were required for stabilization of the kinetics. Conclusions: The TJA exposes athletes to high magnitudes of vertical force. Based on the high variability of performance during early repetitions and the potential to miscategorize high-risk landing in female athletes, practitioners should consider scoring the TJA after 11 successive cycles and using kinetic profiling to support landing assessments. [ABSTRACT FROM AUTHOR]

Pedley, JS, Lloyd, RS, Read, PJ, Moore, IS, Myer, GD, and Oliver, JL. A novel method to categorize stretch-shortening cycle performance across maturity in youth soccer players. J Strength Cond Res 36(9): 2573–2580, 2022—This study used a novel method to categorize stretch-shortening cycle (SSC) function during a drop jump (DJ) using the force-time curve. This method was then used to determine the effect of maturity status upon SSC function and effect of SSC function on DJ performance. Prepeak, circa-peak, and postpeak height velocity male youth soccer players completed a preseason 30-cm DJ onto a force plate. Stretch-shortening cycle function was categorized as poor (impact peak and not spring-like), moderate (impact peak and spring-like), or good (no impact peak and spring-like). Interactions between SSC function and maturity status, and SSC function and kinetic variables were explored. Youth soccer players displaying good SSC function were older and more mature than those with poor SSC function; however, 9.9% of post peak height velocity still displayed poor SSC function. Players with good SSC function recorded significantly shorter ground contact times, reduced time between peak landing and takeoff force, reduced center of mass displacement, and significantly greater takeoff forces than players with moderate and poor SSC function (all p < 0.05). SSC function during a standardized DJ improves with maturation, but a portion of mature players still demonstrate poor SSC function. Good SSC function was associated with improved DJ outcome measures except jump height. Tailored training interventions based on SSC competency may be required to optimally enhance SSC function. [ABSTRACT FROM AUTHOR]

There are currently a multitude of tests used to assess readiness to return to sport (RTS) following anterior cruciate ligament reconstruction (ACLR). The aim of this study was to establish the extent to which movement strategies transfer between three common assessment tasks to help improve design of athlete testing batteries following ACLR. A cohort of 127 male patients 8–10 months post‐ACLR and 45 non‐injured controls took part in the study. Three movement tasks were completed (unilateral and bilateral drop jump, and 90° pre‐planned cut), while ground reaction forces and three‐dimensional kinematics (250 Hz) were recorded. Compared to the bilateral drop jump and cut, the unilateral drop jump had a higher proportion of work done at the ankle (d = 0.29, p < 0.001 and d = −1.87, p < 0.001, respectively), and a lower proportion of work done at the knee during the braking phase of the task (d = 0.447, p < 0.001 and d = 1.56, p < 0.001, respectively). The ACLR group had higher peak hip moments than the non‐injured controls, although the proportion of work done at the ankle, knee and hip joints were similar. Movement strategies were moderately and positively related at the ankle (rs = 0.728, p < 0.001), knee (rs = 0.638, p < 0.001) and hip (rs = 0.593, p < 0.001) between the unilateral and bilateral drop jump, but there was no relationship at the ankle (rs = 0.10, p = 0.104), knee (rs = 0.106, p = 0.166) and hip (rs = −0.019, p = 0.808) between the unilateral drop jump and the cut. Clinicians could therefore consider omitting one of the drop jumps from assessment batteries but should include both jumping and cutting tasks. [ABSTRACT FROM AUTHOR]

Background: Youth populations benefit from neuromuscular training; however, the extent to which training frequency, baseline fitness, and maturity status moderate the response to long-term neuromuscular training in male youth remains unclear.Hypothesis: Twice-weekly training (G2x) would induce larger improvements in movement competency and strength and power kinetics compared with once-weekly training (G1x). Maturity status and baseline fitness would also moderate the training response in strength and power kinetics.Study Design: Nonrandomized, repeated-measures design.Level Of Evidence: Level 3.Methods: Ninety-five male athletes of varying maturity status (pre- or post-peak height velocity) were divided into G2x, G1x, or control (CON) groups. Training groups received G2x or G1x for 28 weeks. Back squat assessment (BSA) movement competency and isometric mid-thigh pull (IMTP), squat jump (SJ), and countermovement jump (CMJ) kinetics were measured pre- and postintervention.Results: The G2x achieved significantly greater adaptations in BSA total score, IMTP allometrically scaled peak force (PFallo), IMTP peak rate-of-force development (PRFD), SJ PFallo and PRFD compared with G1x and CON (P < 0.05; d = 0.3-0.9). Baseline fitness, training frequency and maturity status were significant predictors of IMTP PFallo (R2 = 27.5%) and PRFD (R2 = 42.9%), while a combination of training frequency and baseline fitness explained a small amount of variance in SJ PFallo (R2 = 12.2%) and SJ PRFD (R2 = 6.5%). There were no significant predictors of CMJ kinetics.Conclusion: G2x achieved significantly larger improvements in movement competency, isometric strength and concentric jump variables compared with G1x, with the training response greater in those youth with lower baseline fitness and more advanced maturity status.Clinical Relevance: Exposure to neuromuscular training twice-weekly elicits a greater response than G1x in young male athletes. Practitioners should take maturity status, training frequency, and baseline fitness levels of young male athletes into account when interpreting testing data, as these variables appear to moderate training responsiveness. [ABSTRACT FROM AUTHOR]