Search

Objectives: Describe the injury risk of English youth basketball, comparing game versus training injury incidence and burden.\ud \ud Design: 5 season (2013/14-2018/19) prospective cohort study.\ud \ud Setting: Basketball academy at an English sports college.\ud \ud Participants: Male basketball players (n = 110, mean age; 17.3 ± 0.9 years).\ud \ud Main outcomes measures: Descriptive data regarding game and training injury incidence (injuries per 1000 athlete-exposures (AE)) and burden (severity x incidence) are provided with 95% confidence intervals (CI). Rate ratios (RR; 95% CI) were used to compare outcome measures, with results statistically significant if the 95% CI did not pass 1.0.\ud \ud Results: Fifty-four injuries were sustained during 13,350-AE (1666 games, 9684 training). Game injury incidence (12.0/1000-AE, 95% CI 6.7–17.3) was significantly greater than training injury incidence (2.4/1000-AE, 95% CI 1.4–3.3; RR = 5.1, 95% CI 2.8–9.2). Games had a significantly greater injury burden (216 days absence/1000-AE, 95% CI 121-311) than training (62 days absence/1000-AE, 95% CI 37-88; RR = 3.5, 95% CI 1.9–6.3). The ankle was the most injured body location (37%), whilst over 50% of injuries occurring through contact mechanisms.\ud \ud Conclusion: This study is the most comprehensive description of injury epidemiology in English youth basketball to date. This information can inform evidence-based injury prevention strategies to mitigate risk in this population.

Background\ud Anterior cruciate ligament (ACL) reconstruction has a detrimental impact on athletic performance. Despite rehabilitation guidelines and criterion-based progressions to ensure safe restoration of fundamental physical capacities and maladaptive movement strategies, residual deficits in maximal strength, rate of force development (RFD), power and reactive strength are commonly reported. These combined with associated compensatory inter and intra-limb strategies increase the risk of re-injury.\ud \ud Objective\ud The aim of this article is to examine the relationships between fundamental physical capacities and biomechanical variables during dynamic movement tasks.\ud \ud Design\ud Narrative review\ud \ud Results\ud The available data suggests that quadriceps strength and rate of torque development, explain a moderate portion of the variance in aberrant kinetic and kinematic strategies commonly detected in ACL reconstructed cohorts at who are during the later stages of rehabilitation and RTS\ud \ud Conclusion\ud The available data suggests that quadriceps strength and rate of torque development, explain a moderate portion of the variance in aberrant kinetic and kinematic strategies commonly detected in ACL reconstructed cohorts at who are in the later stages of rehabilitation and RTS

Context: The assessment of pediatric muscle strength is necessary in a range of applications, including rehabilitation programs. Handheld dynamometry (HHD) is considered easy to use, portable, and low cost, but validity to measure lower limb muscle strength in children has not been assessed. Objective: To determine the concurrent validity of lower limb torque from HHD compared with isokinetic dynamometry (ID) in children aged from 7 to 11 years old. Design: A descriptive assessment of concurrent validity of lower limb joint torques from HHD compared with ID. Methods: Sixty-one typically developing children underwent assessment of maximal hip, knee, and ankle isometric torque by HHD and ID using standardized protocols. Joint positions were selected to represent maximal strength and were replicated between devices. Concurrent validity was determined by Pearson correlation, limits of agreement, and Bland–Altman plots. Results: Correlations between HHD and ID were moderate to large for knee extension (r 95% CI, .39 to .73), small to large for plantar flexion (r 95% CI, .29 to .67), knee flexion (r 95% CI, .16 to .59), hip flexion (r 95% CI, .21 to .57), hip extension (r 95% CI, .18 to .54), and hip adduction (r 95% CI, .12 to .56), and small to moderate for dorsiflexion (r 95% CI, −.11 to .39) and hip abduction (r 95% CI, −.02 to .46). Limits of agreement for all joint torques were greater than 10% indicating large error in HHD measured torque compared with ID. A positive proportional bias was detected for plantarflexion, indicating that HHD underestimated torque to a greater extent in participants with higher torque values. Conclusions: Maximal torque values from HHD and ID are consistent with those previously reported in the literature. Poor concurrent validity of HHD may have arisen from issues around joint position, joint stabilization, and the experience of the tester to prevent an isokinetic contraction. Pediatric lower limb muscle strength assessed by HHD should be interpreted with caution.

Injury surveillance systems seek to describe injury risk for a given sport, in order to inform preventative strategies. This often leads to comparisons between studies, although these inferences may be inappropriate, considering the range of methods adopted. This study aimed to describe the injury epidemiology of seven youth sports, enabling valid comparisons of injury risk. Consistent methods were employed across seven sports [male American football, basketball, soccer, rugby league, rugby union; female soccer and rugby union] at a high school in England. A 24-hour time-loss injury definition was adopted. Descriptive statistics and injury incidence (/1000 match-hours) are reported. In total, 322 injuries were sustained by 240 athletes (mean age=17.7±1.0) in 10 273 player-match hours. American football had a significantly greater injury incidence (86/1000 h; 95% CI 61–120) than all sports except female rugby union (54/1000 h; 95% CI 37–76). Concussion was the most common injury (incidence range 0.0–26.7/1000 h), while 59% of injuries occurred via player contact. This study employed standardized data collection methods, allowing valid and reliable comparisons of injury risk between youth sports. This is the first known study to provide epidemiological data for female rugby union, male basketball and American football in an English youth population, enabling the development of preventative strategies.

Resource constraints complicate load monitoring practices in some academies, which is problematic based on load-injury associations surrounding periods of rapid non-linear growth. Limited research has explored relationships between maturation and perceived psycho-physiological response to activity and associated neuromuscular performance changes. This study aimed to quantify neuromuscular and psycho-physiological responses to standardised activity and analyse whether dose-responses were moderated by maturation. Fifty-seven male soccer players (age: 14.1 0.9 years; stature: 165 10 cm; body mass, 57 9 kg; percentage of predicted adult height 92.7 5%) from two Elite Player Performance Plan (EPPP) academies completed the youth soccer-specific aerobic fitness test (Y-SAFT 60). Countermovement jump (CMJ), reactive strength index (RSI), absolute (ABS) and relative leg stiffness (REL) were measured pre-post the Y-SAFT 60 with player-load (PL), heart rate (HR), total distance (TDist) and differential ratings of perceived exertion (dRPE) used as markers of load and intensity. A moderation model was employed to analyse interactions of maturation as a continuous variable. Analysis indicated no significant interaction (p

Clarke, R, Read, PJ, De Ste Croix, MBA, and Hughes, JD. The deceleration deficit: a novel field-based method to quantify deceleration during change of direction performance. J Strength Cond Res 36(9): 2434-2439, 2022-The study investigated the relationship between linear and change of direction (COD) speed performance components and the individual differences between deceleration deficit (DD) and COD deficit (CODD). Thirty-six subjects (mean ± SD : age = 20.3 ± 2.9 years; stature = 175.2 ± 7.7 cm; and body mass = 78.0 ± 16.7 kg) completed 3 trials of a 505 test in both turning directions (dominant [D]; nondominant [ND]) and 3 15-m linear sprints. Deceleration deficit was calculated by the 15-m approach in the 505 test, minus the athlete's linear 15-m sprint time. To compare individuals CODD and DD, z-scores were calculated, and moderate worthwhile changes (MWCs) were identified between these deficit z-scores. Significant correlations were identified between linear sprints and 505 time (D: r = 0.71, 0.74; P0.01. ND: r = 0.76, 0.75; P0.01) for 10-m and 15-m sprint. respectively, and between 505 performance and CODD (D: r = 0.74; P0.01. ND: r = 0.77; P0.01) and DD (D: r = 0.41, P0.05. ND: r = 0.44, P0.01). Deceleration deficit was significantly related to CODD (D: r = 0.59; P0.01. ND: r = 0.62; P0.01); however, 78% of subjects demonstrated differences between these deficit measures greater than an MWC. In conclusion, linear speed has the strongest significant relationship with 505 performance. Deceleration deficit could provide a more isolated construct than CODD which may be related to an athlete's deceleration capabilities.

Physical activity (PA) participation was substantially reduced at the start of the COVID-19 pandemic. The purpose of this study was to assess the association between PA, mental health, and wellbeing during and following the easing of COVID-19 restrictions in the United Kingdom (UK) and New Zealand (NZ). In this study, 3363 adults completed online surveys within 2–6 weeks of initial COVID-19 restrictions (April/May 2020) and once restrictions to human movement had been eased. Outcome measures included the International Physical Activity Questionnaire Short-Form, Depression Anxiety and Stress Scale-9 (mental health) and World Health Organisation-5 Wellbeing Index. There were no differences in PA, mental health or wellbeing between timepoints (p > 0.05). Individuals engaging in moderate or high volume of PA had significantly better mental health (−1.1 and −1.7 units, respectively) and wellbeing (11.4 and 18.6 units, respectively) than individuals who engaged in low PA (p < 0.001). Mental health was better once COVID-19 restrictions were eased (p < 0.001). NZ had better mental health and wellbeing than the UK (p < 0.001). Participation in moderate-to-high volumes of PA was associated with better mental health and wellbeing, both during and following periods of COVID-19 containment, compared to participation in low volumes of PA. Where applicable, during the current or future pandemic(s), moderate-to-high volumes of PA should be encouraged.

Independently, prolonged uninterrupted sitting and the consumption of a meal high in saturated fats acutely disrupt normal cardiovascular function. Currently, the acute effects of these behaviors performed in combination on arterial stiffness, a marker of cardiovascular health, are unknown. This study sought to determine the effect of consuming a high-fat meal (Δ = 51 g fat) in conjunction with prolonged uninterrupted sitting (180 min) on measures of central and peripheral arterial stiffness. Using a randomized crossover design, 13 young healthy males consumed a high-fat (61 g) or low-fat (10 g) meal before 180 min of uninterrupted sitting. Carotid-femoral (cf) and femoral-ankle (fa) pulse wave velocity (PWV), aortic-femoral stiffness gradient (af-SG), superficial femoral PWV beta (β), and oscillometric pulse wave analysis outcomes were assessed pre and post sitting. cfPWV increased significantly more following the high-fat (mean difference [MD] = 0.59 m·s−1) meal than following the low-fat (MD = 0.2 m·s−1) meal, with no change in faPWV in either condition. The af-SG significantly decreased (worsened) (ηp2 = 0.569) over time in the high- and low-fat conditions (ratio = 0.1 and 0.1, respectively). Superficial femoral PWVβ significantly increased over time in the high- and low-fat conditions (ηp2 = 0.321; 0.8 and 0.4 m·s−1, respectively). Triglycerides increased over time in the high-fat trial only (ηp2 = 0.761). There were no significant changes in blood pressure. Consuming a high-fat meal prior to 180 min of uninterrupted sitting augments markers of cardiovascular disease risk more than consuming a low-fat meal prior to sitting.

Objective: To determine which ultrasound-based, single-point arterial stiffness estimate is least dependent on blood pressure to improve assessment of local vascular function. Methods: Ultrasound was used to assess blood flow and diameters at the left brachial artery of twenty healthy adults [55% F, 27.9 y (5.2), 24.2 (2.8) kg/m2]. Blood pressure of both arms was measured simultaneously. Experimental (left) arm blood pressure was then systematically manipulated by adjusting its position ABOVE (+30) and BELOW (-30) heart level in a randomized order following measurement at heart level (0). The control (right) arm remained at heart level. Six stiffness measurements were calculated: compliance, distensibility, beta-stiffness, and three estimates of pulse wave velocity (Bramwell Hill, blood flow, and Beta-stiffness). We considered the measurement technique with the least significant change across positions to be the least pressure-dependent. Results: There was a large effect change in mean arterial pressure (n2p = 0.75, p < 0.001) in the experimental arm when it was ABOVE (∆-4.4 mmHg) and BELOW (∆10.4 mmHg) heart level. There was a main effect (p < 0.05) of arm position on all arterial stiffness measures. From least to most pressure-dependent, the arterial stiffness measurements were: pulse wave velocity (blood flow method), compliance coefficient, beta-stiffness, distensibility coefficient, pulse wave velocity (Bramwell-Hill method), and pulse wave velocity (beta-stiffness index method). Conclusions: All single-point measures assessed are pressure-dependent. The pulse wave velocity (blood flow method) may be the least pressure-dependent single-point measure, and may be the most suitable single-point measure to assess local vascular function.

Hamstring strain injury (HSI) is one of the most prevalent and severe injury in professional soccer. The purpose was to analyze and compare the predictive ability of a range of machine learning techniques to select the best performing injury risk factor model to identify professional soccer players at high risk of HSIs. A total of 96 male professional soccer players underwent a pre-season screening evaluation that included a large number of individual, psychological and neuromuscular measurements. Injury surveillance was prospectively employed to capture all the HSI occurring in the 2013/2014 season. There were 18 HSIs. Injury distribution was 55.6% dominant leg and 44.4% non-dominant leg. The model generated by the SmooteBoostM1 technique with a cost-sensitive ADTree as the base classifier reported the best evaluation criteria (area under the receiver operating characteristic curve score=0.837, true positive rate=77.8%, true negative rate=83.8%) and hence was considered the best for predicting HSI. The prediction model showed moderate to high accuracy for identifying professional soccer players at risk of HSI during pre-season screenings. Therefore, the model developed might help coaches, physical trainers and medical practitioners in the decision-making process for injury prevention.

BACKGROUNDː The most demanding scenarios and physical demands of elite basketball 5-on-5 scrimmages are unknown to trainers, although recent advances in microtechnology allows the gaps in this research to be filled. The purpose of this study was to describe and compare the physical demands, through the most demanding scenarios and traditional average measures, of two different 5-on-5 scrimmage situations executed during training sessions in elite male basketball players.\ud METHODSː Physical demand measures (i.e., total distance covered, high-speed running distance, number of high-intensity accelerations actions, number of high-intensity decelerations actions) were collected from 12 players from the Spanish first Division using a Local Positioning System. Measures were compared via a Bayesian inference analysis, considering playing in half-court (HALF) and half-court and transition (HTRAN) conditions for the 5-on-5 scrimmage.\ud RESULTSː This study showed that, irrespective of the approach used to quantify the physical demands (traditional [average measures per minute] and novel rolling average time epoch [most demanding scenarios]), during the HALF condition players covered less and performed a lower number of high-intensity accelerations and decelerations than in HTRAN (Bayesian factor > 10 and standardized effect size > 0.6). Furthermore, players´ physical demands during 5-on-5 scrimmage situations, independently of the court size, were underestimated consistently by the traditional approach.\ud CONCLUSIONSː Quantifying players´ physical demands through the rolling approach may provide a more accurate measure of the most intense periods of activity. Based on the physical demands described, HTRAN may be used to help train players to perform optimally during the most physically-stressful scenarios of match-play whereas HALF may be more suitable to be included in warm- ups, recovery sessions and sessions immediately before a match.

Kinematic analysis is often performed in a lab using optical cameras combined with reflective markers.\ud With the advent of artificial intelligence techniques such as deep neural networks, it is now possible\ud to perform such analyses without markers, making outdoor applications feasible. In this paper I summarise\ud 2D markerless approaches for estimating joint angles, highlighting their strengths and limitations.\ud In computer science, so-called ‘‘pose estimation” algorithms have existed for many years. These methods\ud involve training a neural network to detect features (e.g. anatomical landmarks) using a process called\ud supervised learning, which requires ‘‘training” images to be manually annotated. Manual labelling has\ud several limitations, including labeller subjectivity, the requirement for anatomical knowledge, and issues\ud related to training data quality and quantity. Neural networks typically require thousands of training\ud examples before they can make accurate predictions, so training datasets are usually labelled by multiple\ud people, each of whom has their own biases, which ultimately affects neural network performance. A\ud recent approach, called transfer learning, involves modifying a model trained to perform a certain task\ud so that it retains some learned features and is then re-trained to perform a new task. This can drastically\ud reduce the required number of training images. Although development is ongoing, existing markerless\ud systems may already be accurate enough for some applications, e.g. coaching or rehabilitation.\ud Accuracy may be further improved by leveraging novel approaches and incorporating realistic physiological\ud constraints, ultimately resulting in low-cost markerless systems that could be deployed both in and\ud outside of the lab.

This study aimed to explore the inter-session reliability of the measures obtained from 2 trunk extension (Biering-Sorensen and Dynamic Extensor Endurance (DEE) tests) and 3 trunk flexion (Ito, Side Bridge and Bench Trunk Curl-Up (BTC) tests) endurance field-based tests in adolescents by sex and age. A total of 208 (males, n = 100; females, n = 108) adolescents (ranging from 12 to 18 years) performed all the field-based tests on 2 separate testing sessions, 7-days apart. The inter-session reliability scores were explored for the total sample and by sex and age groups through relative reliability (intraclass correlation coefficient (ICC)), inter-session differences (systematic bias) and precision of measurements (i.e. absolute reliability) (standard error of measurement expressed as a percentage of the mean score (CVTE) and minimal detectable change (MDC95)). The sensitivity of each test was also assessed through the smallest worthwhile percentage change (SWC). No relevant sex and age groups differences were found for either test-retest reliability or sensitivity in each test, so the grouped scores were considered as generalizable for this cohort of high school-aged adolescents. Most of the trunk endurance measures demonstrated acceptable relative reliability (ICCs ranged from 0.75 to 0.94). However, significant inter-session differences were identified for measures from the DEE and BTC tests. Likewise, the precision of the measurement of each field-based test was poor (CVTE ranged from 11.3 to 24.4%) with the MDC95 revealing that changes higher than 42% for trunk extension endurance tests and 31.4% for trunk flexion endurance tests after an intervention are required to indicate a significant change above measurement error. All tests were sensitive enough to detect moderate to large changes in trunk muscle endurance. Therefore, the findings from this study indicate that only the BTC test demonstrates acceptable inter-session reliability (ICC > 0.9, CVTE ~ 10%, MDC95 ~ 30%) to monitor the changes in trunk endurance scores that may be expected in adolescents after performing an intervention program. The use of supervised familiarization sessions before performing the tests and strong encouragement to perform a maximal effort in each test may be helpful strategies to improve the reliability scores.

Purpose: To examine the influence of growth and maturation in the trajectory of stretch-shortening cycle capability. Method: Using a mixed-longitudinal design, absolute and relative leg stiffness and reactive strength index (RSI) were measured 3 times over a 3-year period in 44 youth team-sport players. Maturation was determined as maturity offset and included within the Bayesian inference analysis as a covariate alongside chronological age. Results: Irrespective of age and maturation, there was no change in absolute leg stiffness, however relative leg stiffness decreased over time. Maturation and age reduced this decline, but the decline remained significant (Bayesian factor [10] = 5097, model averaged R2 = .61). The RSI increased over time and more so in older more mature youth players (Bayesian factor [10] = 9.29e8, model averaged R2 = .657). Conclusion: In youth players who are at/post peak height velocity, relative leg stiffness appears to decline, which could have an impact on both performance and injury risk. However, RSI increases during this period, and these data reinforce that leg stiffness and RSI reflect different components of stretch-shortening cycle capability. Practitioners should consider these differences when planning training to maximize stretch-shortening cycle capability during growth and maturation in athletes on the developmental performance pathway.

Objectives\ud To determine whether back foot (BF) position influences dorsiflexion range of motion (DFROM) during three different positions of the weight bearing lunge test (WBLT).\ud Design\ud Randomised, repeated measures design\ud Setting \ud Sports clubs\ud Participants\ud 52 athletes participating in cutting and pivoting sports\ud Main Outcome measures \ud DFROM was obtained using a WBLT in three different BF positions: BF heel in full contact with the floor, BF heel raised off the floor and BF was non weight bearing (NWB). All measurements were obtained using three methods: inclinometer at the tibial tuberosity, toe to wall distance and goniometer angle from the lateral malleolus to the fibula head. Differences between testing positions were determined using a repeated measures one-way ANOVA and reliability analysis was performed using the Intraclass Correlation Coefficient (ICC).\ud Results \ud DFROM was statistically significantly different for all three positions of the WBLT for each measurement technique (P

Context: Despite the popularity of jump-landing tasks being used to identify injury risk factors, minimal data currently exist examining differences in knee kinematics during commonly used bilateral jumping tasks. This is especially the case for rebounding-based protocols involving young athletes. Objective: To compare the frontal plane projection angles (FPPAs) during the drop vertical jump (DVJ) and tuck jump assessment (TJA) in a cohort of elite male youth soccer players of varying maturity status. Methods: A total of 57 male youth soccer players from an English championship soccer club participated in this study. Participants performed 3 trials of the DVJ and TJA, during which movement was recorded with 2-dimensional video cameras. FPPA for both right (FPPA-r) and left (FPPA-l) legs, with values Results: On a whole-group level, FPPA-r (172.7° [7.4°] vs 177.2° [11.7°]; P l (173.4° [7.3°] vs 179.2° [11.0°]; P ES = 0.62) were significantly greater for both limbs in the TJA compared with the DVJ; however, these differences were less consistent when grouped by maturity status. FPPA-r during the TJA was significantly and moderately greater in the circa-peak height velocity (PHV) group compared with the post-PHV cohorts (169.4° [6.4°] vs 175.3° [7.8°]; P ES = 0.49). Whole-group data showed moderate relationships for FPPA-r and FPPA-l between the TJA and DVJ; however, stronger relationships were shown in circa- and post-PHV players compared with the pre-PHV cohort. Conclusions: Considering that the TJA exposed players to a larger FPPA and was sensitive to between-group differences in FPPA-r, the TJA could be viewed as a more suitable screen for identifying FPPA in young male soccer players.

Rugby (union and league) has come under intense scrutiny due to its injury risk. Various interventions have been introduced to protect players from injury, with many deemed efficacious and advocated for use across various worldwide contexts. However, their implementation is less clear. The objective of this systematic review was to determine whether injury prevention interventions in rugby have evaluated their ‘reach’, ‘effectiveness’, ‘adoption’, ‘implementation’ and ‘maintenance’ as per the RE-AIM Multi-Dimension Item Checklist. Six electronic databases were searched in November 2019. Inclusion criteria included: English language, peer-reviewed journal article, original research, field-based rugby code, prospective intervention. Of the 4253 studies identified, 74 met the full inclusion criteria. Protective equipment, predominately mouthguards, was the intervention of interest in 44 studies. Other interventions included multimodal national injury prevention programmes, law changes and neuromuscular training programmes. ‘Effectiveness’ was the highest scoring RE-AIM dimension (55%), followed by ‘reach’ (26%). All other RE-AIM dimensions scored below 20%. Research currently focuses on determining intervention ‘effectiveness’. For injury prevention strategies to have their desired impact, there must be a shift to address all determinants associated with implementation. Consideration should be given to how this can be achieved by adopting specific reporting checklists, research frameworks and study designs.

Background: The triple hop for distance test commonly uses a limb symmetry index (LSI) ‘pass’ threshold of N90% for total hop distance following anterior cruciate ligament reconstruction (ACLR). However, understanding the manner in which athletes generate and dissipate forces during consecutive hops within the test may provide greater insight into residual limb deficits. The aim of the study was to examine reactive strength ratios (RSR) of individual hops during a triple hop test in a cohort of ACLR patients at discharge prior to return-to-sport. Methods: Twenty male athletes (24.6 ± 4.2 years; height 175.3 ± 10.2 cm; mass 73.6 ± 14.5 kg) completed the test on both non-operated and operated limbs. Total distance hopped, contact times, flight times and RSR were collected for each hop using a floor-level optical measurement system. Results: Significant, small to moderate between-limb differences (p b 0.05; d = 0.45–0.72) were shown for triple hop distance, flight time and RSR for each hop, with lower performance consistently displayed in the operated limb. Large, significant differences in RSR were evident between hops one and two on the operated limb (p b 0.05; d = 0.97). Despite 80% of participants achieving N90% LSI for total hop distance, less than 50% of participants reached the N90% LSI threshold for RSR. Conclusions: Standardised LSI ‘pass’ thresholds (N90% LSI) for triple hop distance may mask residual deficits in reactive strength performance of operated limbs; therefore, more detailed analyses of individual hop performance may be warranted to enhance return to sport criteria following ACLR.

Moeskops, S, Oliver, JL, Read, PJ, Cronin, JB, Myer, GD, Haff, GG, and Lloyd, RS. The influence of biological maturity and competitive level on isometric force-time curve variables and vaulting performance in young female gymnasts. J Strength Cond Res 34(8): 2136-2145, 2020-This cross-sectional study investigated isometric force-time curve variables and vaulting performance in young female gymnasts of varying maturity and competitive levels. One hundred twenty gymnasts aged 5-14 years were subdivided into maturity groupings and also according to their competitive level. Subjects performed isometric midthigh pulls (IMTP) before completing straight jump vaults that were recorded using two-dimensional video. All significance values were accepted at p < 0.05. Absolute peak force (PF abs) and force at various time epochs were significantly greater in more mature gymnasts, although no significant differences were observed in relative peak force (PF rel). When grouped by competitive level, elite gymnasts produced a significantly greater absolute rate of force development (RFD abs) at 0-150, 0-200, and 0-250 ms as well as relative RFD (RFD rel) at 0-200 and 0-250 ms than recreational gymnasts. Based upon regression analyses, force at 50 ms during the IMTP test explained 15% of vertical takeoff velocity during vaulting. Biological maturation seems to impact isometric force-time curve characteristics in young female gymnasts, and higher-level gymnasts produce greater RFD than those competing at a lower level. Vaulting vertical takeoff velocity seems to be largely independent of isometric force-time characteristics with only a small amount of variance explained by force at 50 ms.

Pulse wave analysis (PWA) utilizes arm blood pressure (BP) waveforms to estimate aortic waveforms. The accuracy of central BP waveform estimation may be influenced by assessment site local haemodynamics. This study investigated whether local haemodynamic changes, induced via arm tilting ±30° relative to heart level, affect estimated central systolic BP (cSBP) and arterial wave reflection (central augmentation index, cAIx; aortic backward pressure wave, Pb). In 20 healthy adults (26.7 years [SD 5.2], 10 F) brachial BP waveforms were simultaneously recorded on experimental and control arms. The experimental arm was randomly repositioned three times (heart level, -30° heart level, +30° heart level), while the control arm remained fixed at heart level. For the experimental arm, arm repositioning resulted in a large (partial eta-squared 0.14) effect size (ES) change in SBP (ES = 0.75, P 0.001), cSBP (ES = 0.81, P 0.001), and cAIx (ES = 0.75, P = 0.002), but not Pb (ES = 0.06, P = 0.38). In the control arm, cAIx (ES = 0.22, P = 0.013) but not SBP or cSBP significantly changed. Change in experimental arm cSBP was partially explained by brachial systolic blood velocity (P = 0.026) and mean diameter (P = 0.012), while change in cAIx was associated with brachial retrograde blood velocity (P = 0.020) and beta stiffness (P = 0.038). In conclusion, manipulation of assessment site local haemodynamics, including the blood velocity profile and local arterial stiffness, had a large effect on estimated cSBP and cAIx, but not on Pb. These findings do not invalidate PWA devices but do suggest that the accuracy of the estimated aortic pressure waveform is dependent on stable peripheral haemodynamics.

Kinematic analysis is often performed with a camera system combined with reflective markers placed over bony landmarks. This method is restrictive (and often expensive), and limits the ability to perform analyses outside of the lab. In the present study, we used a markerless deep learning-based method to perform 2D kinematic analysis of deep water running, a task that poses several challenges to image processing methods. A single GoPro camera recorded sagittal plane lower limb motion. A deep neural network was trained using data from 17 individuals, and then used to predict the locations of markers that approximated joint centres. We found that 300–400 labelled images were sufficient to train the network to be able to position joint markers with an accuracy similar to that of a human labeler (mean difference < 3 pixels, around 1 cm). This level of accuracy is sufficient for many 2D applications, such as sports biomechanics, coaching/training, and rehabilitation. The method was sensitive enough to differentiate between closely-spaced running cadences (45–85 strides per minute in increments of 5). We also found high test–retest reliability of mean stride data, with between-session correlation coefficients of 0.90–0.97. Our approach represents a low-cost, adaptable solution for kinematic analysis, and could easily be modified for use in other movements and settings. Using additional cameras, this approach could also be used to perform 3D analyses. The method presented here may have broad applications in different fields, for example by enabling markerless motion analysis to be performed during rehabilitation, training or even competition environments.

Vinson, D, Gerrett, N, and James, DVB. Influences of playing position and quality of opposition on standardized relative distance covered in domestic women's field hockey: Implications for coaches. J Strength Cond Res 32(6): 1770-1777, 2018-The purpose of this study was to compare the standardized relative distance covered by the various playing positions (defenders, midfielders, and forwards) against different quality of opponents in domestic women's field hockey. Data were collected from 13 individuals competing for 1 team in the English Premier League across an 18-game season. Data were collected using portable global positioning system technology. Distance data were grouped into 6 speed zones relative to individual players' maximum sprint speeds and then standardized by dividing by the number of on-pitch minutes. Dependent variables included distance covered in the 6 speed zones, as well as the number of sprints and repeated sprint efforts (RSEs) completed in the highest speed zone. Participants covered a significantly greater total distance when competing against opponents from top 3 teams compared with middle 3 teams (111.78 ± 2.65 m·min vs. 107.35 ± 2.62 m·min, respectively). This was also true for distance covered in zone 4 (running) (29.47 ± 1.69 m·min vs. 27.62 ± 1.45 m·min, respectively) and zone 5 (fast running) (23.42 ± 1.76 m·min vs. 21.52 ± 1.79 m·min, respectively). Defenders (99.77 ± 4.36 m·min) covered significantly less total meters per minute than midfielders (117.20 ± 4.36 m·min) and completed significantly fewer RSEs per on-pitch minute (0.21 ± 0.03 and 0.33 ± 0.03, respectively). Midfielders covered significantly less distance in zone 2 (walking) than forwards (19.38 ± 1.64 m·min and 30.33 ± 2.12 m·min, respectively). Conversely, midfielders were shown to cover significantly more distance in zone 3 (jogging) than forwards (32.84 ± 1.10 m·min and 24.61 ± 1.42 m·min, respectively). A standardized and relative assessment may be useful for coaches' and performance analysts' understanding of players' performance in different positions or against different quality opponents.

Background\ud Ghrelin is a gut hormone with numerous physiological effects, including the regulation of energy balance, insulin sensitivity, vascular health, and body composition. Acylated (AG) and des-acylated (DAG) ghrelin constitute approximately 22 % and 78 % of total plasma ghrelin (TG), respectively. Alterations in the TG concentration and the AG/DAG ratio may be implicated in conditions involving energy imbalances and insulin resistant states (e.g., metabolic syndrome or Type 2 diabetes mellitus). Exercise is a therapeutic option that can potentially optimize ghrelin levels. Understanding the precise intensity and dose of exercise to optimize ghrelin levels may lead to targeted interventions to restore metabolic regulation in obesity and other clinical conditions.\ud \ud Objective\ud To perform a systematic review and meta-analysis on the effects of acute exercise on pre-prandial levels of TG, AG, and DAG in healthy adults and to determine if sample demographics or exercise doses moderate such effects.\ud \ud Methods\ud Electronic databases (PubMed, Medline, SPORTDiscus, Web of Science, and Google Scholar) were searched with articles published through August 2020. The following criteria was determined a priori for article inclusion: (i) the study was a randomized controlled trial (RCT),(ii) exercise was an acute bout, (iii) the exercise bout for the intervention group(s)/condition was structured, (iv) the control group/condition received no exercise, (v) participants were adults age 18 or older, (vi) ghrelin was sampled through blood, (vii) there was at least one baseline measure and one post-exercise measure of ghrelin, (viii) there were at least 3 timepoints where ghrelin was measured while participants were fasted to allow for pre-prandial total area-under-the-curve (AUCtotal) calculation, (ix) participants were healthy with no overt disease, (x) interventions were carried out without any environmental manipulations. Standardized mean difference (SMD) with 95 % confidence intervals were calculated using the restricted maximum likelihood estimation Moderator analyses to determine whether the overall pooled effect was influenced by: sex, ghrelin form, method of ghrelin analysis, age, body mass index, body fat percentage, fitness, intensity of exercise bout, duration of exercise bout, energy expenditure, and length of AUCtotal data.\ud \ud Results\ud The analysis included 24 studies that consisted of 52 trials, n = 504 (age 27.0 (8.8) years, BMI 24.7 (2.7) kg/m2) and measured AG (n = 38 trials), DAG (n = 7), and TG (n = 7). The overall model indicated that exercise lowered ghrelin levels compared to control (no exercise); (SMD=-0.44, p < 0.001), and exercise intensity exhibited an inverse relationship with ghrelin levels (regression coefficient (ß)=-0.016, p = 0.04). There was no significant difference by ghrelin form (p = 0.18).\ud \ud Discussion\ud Acute exercise significantly lowers plasma ghrelin levels, with higher intensity exercise associated with greater ghrelin suppression. The majority of studies applied a moderate intensity exercise bout and measured AG, with limited data on DAG. This exercise dose may be clinically significant in individuals with metabolic dysregulation and energy imbalance as a therapy to optimize AG levels. More work is needed to compare moderate and high intensity exercise and the ghrelin response in clinical populations.

Background. Despite the reported beneficial effects of physical activity (PA) during and after cancer diagnosis, current research data suggest that the percentages of breast cancer survivors who adhere to PA recommendations are low. The objective of the present systematic, critical review was to identify, analyze, and provide a summary of qualitative literature findings, which have explored breast cancer survivors’ experiences of participating in an exercise/PA intervention after cancer treatment.\ud \ud Methods. A systematic search was conducted using CINAHL, PsychINFO, PubMed, and Scopus electronic databases to search for qualitative literature published during 2000–2016. A total of six studies that met the inclusion criteria were reviewed. Thematic synthesis, following Thomas and Harden’s methods, were used to analyze the data.\ud \ud Findings. Seven descriptive themes were developed: control, focus, transitioning phase, regaining a sense of confidence, enhanced spirits, social support, and safe environment. The findings suggested that participation in supervised exercise interventions enhanced the self-confidence and mood of breast cancer survivors. It allowed them to regain control and provide a focus, thereby allowing them to move forward in their lives.\ud \ud Conclusion. The results of this systematic critical review indicated that the supervised exercise was a positive experience for breast cancer survivors.

Regulations now state that professional academies in the United Kingdom are required to substantially increase the volume of soccer training. The purpose of this study was to assess the current injury occurrence, providing an update to reports published prior to the introduction of the Elite Player Performance Plan (EPPP). 608 elite male youth soccer players aged 11 – 18 years from the academies of six professional soccer clubs were prospectively monitored, recording injuries during the 2014-2015 soccer season. An injury rate of 1.32 injuries per player / season was indicated with a mean time loss of 21.9 days per injury. The greatest time loss per injury was in the U14s-U15s, and the highest rate of severe injuries in the U15s. Strains and sprains were the most common injury type, with the knee and ankle the most frequently injured anatomical sites. Seasonal variation indicated two peaks in injury incidence, occurring in September and January. In comparison to a published audit prior to the inception of the EPPP, this study indicates that academy soccer players are three-times more likely to experience an injury. Given that time loss and injury severity also increased during periods that typically follow rapid growth, these players should be considered an important focus group for training load monitoring and injury prevention strategies.

Introduction \ud Hamstring strain injuries typically occur in the proximal biceps femoris long head (BFlh) at high running speeds. Strain magnitude seems to be the primary determinant of strain injury, and may be regulated by muscle activation. In running, BFlh strain is largest in the proximal region, especially at high speeds. However, region-specific activity has not been examined. This study examined the proximal–distal and intermuscular activity of BFlh and semitendinosus (ST) as a function of increasing running speed.\ud \ud Methods \ud Thirteen participants ran at steady speeds of 4.1 (slow), 5.4 (moderate), and 6.8 m·s−1 (fast) on a treadmill. Region- and muscle-specific EMG activity were recorded at each speed using high-density EMG, and were normalized to maximal voluntary isometric activity. Muscle–tendon unit lengths were calculated from kinematic recordings. Speed effects, regional, and intermuscular differences were tested with Statistical Parametric Mapping.\ud \ud Results \ud With increasing running speed, EMG activity increased in all regions of both muscles to a similar extent in the clinically relevant late swing phase. Increases in muscle–tendon unit lengths in late swing as a function of running speed were comparatively small. In fast running, EMG activity was highest in late swing in all regions, and reached 115% ± 20% (proximal region, mean ± 95% confidence limit), 106% ± 11% (middle), and 124% ± 16% (distal) relative to maximal voluntary isometric activity in BFlh. Regional and intermuscular EMG patterns were highly individual, but each individual maintained similar proximal–distal and intermuscular EMG activity patterns across running speeds.\ud \ud Conclusions \ud Running is associated with highly individual hamstring activity patterns, but these patterns are similar across speeds. It may thus be crucial to implement running at submaximal speeds early after hamstring injury for restoration of normal neuromuscular function.

Heelas, T, Theis, N, and Hughes, JD. Muscle activation patterns during variable resistance deadlift training with and without elastic bands. J Strength Cond Res XX(X): 000-000, 2019-The purpose of this study was to determine the effects of band-assisted variable resistance training on muscular activity in the lower limbs and barbell kinematics during the concentric phase of the deadlift. Fifteen resistance trained men (mean ± SD: 28.7 ± 9.3 years; 1.80 ± 0.90 m; 92.5 ± 15.1 kg) performed 6 deadlift repetitions during 4 loading conditions: 100-kg bar (no band), 80-kg bar with 20-kg band tension (B20), 75-kg bar with 25-kg band tension (B25), and 70-kg bar with 30-kg band tension (B30). Muscle activity from the medial gastrocnemius (MG), semitendinosus (ST), vastus medialis (VMO), vastus lateralis (VL), and gluteus maximus (GM) were recorded using surface electromyography during the concentric phase of the lift and expressed as a percentage of each muscle's maximal activity, recorded during a maximal isometric contraction. Barbell power and velocity were recorded using a linear position transducer. Electromyography results showed that muscle activity significantly decreased as band resistance increased in the MG and ST (p < 0.05) and progressively decreased in the GM. No changes were observed for the VMO or VL. Peak and mean bar velocity and power significantly increased as band resistance increased. Performing the deadlift with band-assisted variable resistance increases bar power and velocity, while concurrently decreasing muscle activation of the posterior chain musculature. Practitioners prescribing this exercise may wish to include additional posterior chain exercises that have been shown to elicit high levels of muscle activation.

NEW FINDINGS What is the central question of this study? There is growing interest in the effects of sedentarism on central and peripheral cardiovascular health. To permit further investigation, including larger epidemiological studies, there is a need to identify arterial health assessment tools that are valid (accurate) and reliable (precise), yet practical. What is the main finding and its importance? Lower-limb vascular health (femoral-ankle pulse-wave velocity) can be determined in a supine position with accuracy and precision using an oscillometrically based device. This technology might help to improve our understanding of the pathological mechanisms linking cardiovascular disease to sedentarism, including the interaction between peripheral and central vasculature. ABSTRACT There is a growing interest in the deleterious effects of sedentary behaviour on lower-limb arterial health. To permit further investigation, including larger epidemiological studies, there is a need to identify lower-limb arterial health assessment tools that are valid and reliable, yet simple to administer. In this study, we sought to determine the validity and between-day reliability of femoral-ankle pulse-wave velocity (faPWV) measures obtained using an oscillometrically based device (SphygmocCor XCEL) in supine and seated positions. Doppler ultrasound was used as the criterion. A total of 47 healthy adults were recruited for validity (n = 32) and reliability (n = 15) analyses. Validity was determined by measuring faPWV in seated and supine positions using the XCEL and Doppler ultrasound devices, in a randomized order. Between-day reliability was determined by measuring seated and supine faPWV using the XCEL on three different mornings, separated by a maximum of 7 days. The validity criterion [absolute standard error of estimate (aSEE)

The main purpose of this study was to analyse the training effects of the FIFA 11+ and\ud Harmoknee on several parameters of physical performance measures in youth amateur\ud football players. Forty-one adolescent players were randomised within each team into two\ud groups (team 1: control vs. FIFA 11+; team 2: control vs. Harmoknee). The FIFA 11+ and\ud Harmoknee groups performed the program 3 times a week for 4 weeks; the control groups\ud completed their usual warm-up routines. Thirteen physical performance measures (joint range\ud of motion, dynamic postural control, single legged hop limb symmetry, sprint time, jumping\ud height and agility) were assessed. All physical performance parameters were compared via a\ud magnitude-based inference analysis. Significant between-group differences (in favour of the\ud FIFA 11+ players) were found for dynamic postural control (anterior [2.5%] and\ud posteromedial [7.2%] distances), single legged hop limb symmetry (side-to-side symmetry\ud during a triple hop test [8.3%]), 10 (8.4%) and 20 (1.8%) m sprint times and jumping height\ud (9.1%) neuromuscular outcomes. For the Harmoknee, significant differences (in comparison\ud to its paired control group) were found only for 10 (2.7%) and 20 (2.9%) m sprint times and\ud jumping height (9.7%). Therefore, the main findings of this study suggest exchanging\ud traditional warm-up programmes for the FIFA 11+ in male youth soccer players based on its\ud superior effects on some neuromuscular parameters (sprinting, jumping and stability) of\ud physical performance.

We investigated how inspiratory muscle training impacted respiratory and locomotor muscle deoxygenation during submaximal exercise with resistive inspiratory loading. 16 male cyclists completed 6 weeks of either true (n=8) or sham (n=8) inspiratory muscle training. Pre- and post-training, subjects completed 3, 6-min experimental trials performed at ~80% ˙VO2peak with interventions of either moderate inspiratory loading, heavy inspiratory loading, or maximal exercise imposed in the final 3 min. Locomotor and respiratory muscle oxy-, deoxy-, and total-haemoglobin and myoglobin concentration was continuously monitored using near-infrared spectroscopy. Locomotor muscle deoxygenation changes from 80% ˙VO2peak to heavy inspiratory loading were significantly reduced pre- to post-training from 4.3±5.6 µM to 2.7±4.7 µM. Respiratory muscle deoxygenation was also significantly reduced during the heavy inspiratory loading trial (4.6±3.5 µM to 1.9±1.5 µM) post-training. There was no significant difference in oxy-, deoxy-, or total-haemoglobin and myoglobin during any of the other loading trials, from pre- to post-training, in either group. After inspiratory muscle training, highly-trained cyclists exhibited decreased locomotor and respiratory muscle deoxygenation during exercise with heavy inspiratory loading. These data suggest that inspiratory muscle training reduces oxygen extraction by the active respiratory and limb muscles, which may reflect changes in respiratory and locomotor muscle oxygen delivery.

Early specialisation is characterised by formal participation in a single sport at the exclusion of others. Limited data are available to support this approach in the development of soccer players who attain elite status later in life. Of growing concern is the associated increased risk of injury and suggestions that single sport specialisation is a risk factor independent of age, growth, biological maturation and training volumes. In the United Kingdom, elite soccer organisations have recently adopted an early sport specialisation approach following the introduction of the Elite Player Performance Plan. A key tenet of this programme is increased opportunities for training through a marked rise in the specified on-pitch hours per week. The accumulation of high training hours may be less of a relevant marker for success, and the impact of such a significant increase in training volume for young athletes who are experiencing a range of growth and maturational processes is currently unknown. This critical commentary includes an evidence-based discussion of the effectiveness of early sport specialisation and the potential injury risks associated with such programmes placing a specific focus on elite male youth soccer players. Available data indicate that modifications to the existing Elite Player Performance Plan framework could enhance players' development and reduce injury risk. Proposed alterations include reduced volume of soccer-specific training at key stages of growth and maturation and guidelines for the provision of a greater variety of physical activities that are integrated within other programme components.

Purpose: Marathon and ultramarathon provoke respiratory muscle fatigue and pulmonary dysfunction; nevertheless, it is unknown how the respiratory system responds to multiple, consecutive days of endurance exercise.\ud \ud Methods: Nine trained individuals (six male) contested 10 marathons in 10 consecutive days. Respiratory muscle strength (maximum static inspiratory and expiratory mouth-pressures), pulmonary function (spirometry), perceptual ratings of respiratory muscle soreness (Visual Analogue Scale), breathlessness (dyspnea, modified Borg CR10 scale), and symptoms of Upper Respiratory Tract Infection (URTI), were assessed before and after marathons on days 1, 4, 7, and 10.\ud \ud Results: Group mean time for 10 marathons was 276 ± 35 min. Relative to pre-challenge baseline (159 ± 32 cmH2O), MEP was reduced after day 1 (136 ± 31 cmH2O, p = 0.017), day 7 (138 ± 42 cmH2O, p = 0.035), and day 10 (130 ± 41 cmH2O, p = 0.008). There was no change in pre-marathon MEP across days 1, 4, 7, or 10 (p > 0.05). Pre-marathon forced vital capacity was significantly diminished at day 4 (4.74 ± 1.09 versus 4.56 ± 1.09 L, p = 0.035), remaining below baseline at day 7 (p = 0.045) and day 10 (p = 0.015). There were no changes in FEV1, FEV1/FVC, PEF, MIP, or respiratory perceptions during the course of the challenge (p > 0.05). In the 15-day post-challenge period, 5/9 (56%) runners reported symptoms of URTI, relative to 1/9 (11%) pre-challenge.\ud \ud Conclusions: Single-stage marathon provokes acute expiratory muscle fatigue which may have implications for health and/or performance, but 10 consecutive days of marathon running does not elicit cumulative (chronic) changes in respiratory function or perceptions of dyspnea. These data allude to the robustness of the healthy respiratory system.

BACKGROUND: Limited ranges of motion (ROM) has been considered as a primary risk factor for some football injuries, but only a few studies have analysed differences in lower extremity joints. The main purposes were (a) to describe the lower extremity ROM profile in professional football players; and (b) to examine differences between goalkeepers and outfield players.\ud METHODS: 82 professional male football players from 4 teams were measured in the 2013 pre-season. Measures of passive hip (flexion with knee flexed [PHFKF] and extended [PHFKE], extension [PHE], abduction [PHA], external [PHER] and internal [PHIR] rotation), knee (flexion [PKF]) and ankle (dorsiflexion with knee flexed [ADFKF] and extended [ADFKE]) ROMs were taken. Magnitude-based inferences exploring differences between player position and limb were made.\ud RESULTS: 46% of all participants showed restricted PHFKE and/or around 30% showed restricted ADFKF ROM values. Contrarily, most players reported normal PHFKF, PHE, PHIR and PHER as well as PKF ROM scores with percentage values close to 100%. Bilateral meaningful differences for PHA, PHIR and PHER were found in approximately 30% of outfield players and goalkeepers. Statistical analysis found trivial differences between players for PHFKE, PHE, PHIR, PHER, ADFKE and ADFKF. However, moderate differences between players were found for PHFKF, PHA and PKF, with goalkeepers demonstrating higher values than outfield players. \ud CONCLUSIONS: The findings of this study reinforce the necessity of prescribing exercises aimed at improving PHFKE and ADFKF ROM within everyday football training routines. In addition, as some bilateral deficits were observed, unilateral training should be considered where appropriate.

Objectives\ud The aim of this study was to examine the validity of the International Physical Activity Questionnaire Short Form (IPAQ-SF) as a measure of physical activity (PA) in young people with cerebral palsy (CP).\ud Design\ud Cross-sectional.\ud Setting\ud Participants were recruited through 8 National Health Service (NHS) trusts, one school, one university and through organisations that provide services for people with disabilities in England.\ud Participants\ud Sixty-four, ambulatory young people aged 10-19 years with CP [Gross Motor Function Classification System (GMFCS) levels I–III] participated in this study.\ud Main outcome measure\ud The IPAQ-SF was administered to participants. Participants were then asked to wear a wGT3X-BT triaxial accelerometer (ActiGraph, Pensacola, FL) for 7 days to objectively assess PA. Time spent in sedentary behaviour, in moderate to vigorous PA (MVPA) and in total PA (TPA) was compared between measures.\ud Results\ud Young people with CP self-reported less time in sedentary behaviour and underestimated the time spent in TPA,when compared to accelerometer measurements. Bland-Altman plots demonstrated poor agreement between the measures for MVPA, with upper and lower 95% limits of agreement of -147.23 to 148.9 min. After adjusting for gender and GMFCS level, age was a predictor of the difference between measures for MVPA (p

The aim of this study was to examine strategies to absorb impact shock during\ud RaceRunning in participants with neurological motor disorders. For this purpose,\ud eight RaceRunning athletes (four males and four females) voluntarily took part in\ud this study. Each participant performed a series of 100-m sprints with a RaceRunning bike. Acceleration of the tibia and head was measured with two inertial\ud measurement units and used to calculate foot impact shock measures. Results\ud showed that RaceRunning pattern was characterized by a lack of impact peak in\ud foot–ground contact time and the existence of an active peak after foot contact.\ud Due to the ergonomic properties of the RaceRunning bike, shock is attenuated\ud throughout the stance phase. In conclusion, the resultsrevealed that RaceRunning\ud athletes with neurological motor disorders are capable of absorbing impact shock\ud during assisted RaceRunning using a strategy that mimics runners without\ud disabilities

Previous studies have shown that aging is associated with alterations in muscle architecture and tendon properties (Morse CI, Thom JM, Birch KM, Narici MV. Acta Physiol Scand 183: 291–298, 2005; Narici MV, Maganaris CN, Reeves ND, Capodaglio P. J Appl Physiol 95: 2229–2234, 2003; Stenroth L, Peltonen J, Cronin NJ, Sipila S, Finni T. J Appl Physiol 113: 1537–1544, 2012). However, the possible influence of different types of regular exercise loading on muscle architecture and tendon properties in older adults is poorly understood. To address this, triceps surae muscle-tendon properties were examined in older male endurance (OE, n = 10, age = 74.0 ± 2.8 yr) and sprint runners (OS, n = 10, age = 74.4 ± 2.8 yr), with an average of 42 yr of regular training experience, and compared with age-matched [older control (OC), n = 33, age = 74.8 ± 3.6 yr] and young untrained controls (YC, n = 18, age = 23.7 ± 2.0 yr). Compared with YC, Achilles tendon cross-sectional area (CSA) was 22% ( P = 0.022), 45% ( P = 0.001), and 71% ( P < 0.001) larger in OC, OE, and OS, respectively. Among older groups, OS had significantly larger tendon CSA compared with OC ( P = 0.033). No significant between-group differences were observed in Achilles tendon stiffness. In older groups, Young's modulus was 31-44%, and maximal tendon stress 44–55% lower, than in YC ( P ≤ 0.001). OE showed shorter soleus fascicle length than both OC ( P < 0.05) and YC ( P < 0.05). These data suggest that long-term running does not counteract the previously reported age-related increase in tendon CSA, but, instead, may have an additive effect. The greatest Achilles tendon CSA was observed in OS followed by OE and OC, suggesting that adaptation to running exercise is loading intensity dependent. Achilles tendon stiffness was maintained in older groups, even though all older groups displayed larger tendon CSA and lower tendon Young's modulus. Shorter soleus muscle fascicles in OE runners may be an adaptation to life-long endurance running.

To examine and compare sex-related differences in the functioning of the hamstrings and quadriceps muscles and the isokinetic hamstrings eccentric-to-quadriceps concentric functional ratio (H/Q FUNC). Fifty male and 46 female young adults completed this study. Each participant carried out an isokinetic assessment to determine isokinetic concentric and eccentric torques during knee extension and flexion actions at 3 different angular velocities (60, 180 and 300°/s) adopting a lying position. The H/Q FUNC was calculated using peak torque (PT) values and 3 different joint-angle-specific torque values (15°, 30° and 45° of knee extension). A repeated measures analysis of variance was used to compare the results, and post hoc analyses using Friedman correction were employed. There were statistically significant effects of angular velocity, joint angle and sex on the H/Q FUNC (p

Purpose:Previous literature has presented pacing data of groups of competition finalists. The aim of this study was to analyze the pacing patterns displayed by medalists and nonmedalists in international competitive 400-m swimming and 1500-m running finals.Methods:Split times were collected from 48 swimming finalists (four 100-m laps) and 60 running finalists (4 laps) in international competitions from 2004 to 2012. Using a cross-sectional design, lap speeds were normalized to whole-race speed and compared to identify variations of pace between groups of medalists and nonmedalists. Lap-speed variations relative to the gold medalist were compared for the whole field.Results:In 400-m swimming the medalist group demonstrated greater variation in speed than the nonmedalist group, being relatively faster in the final lap (P < .001; moderate effect) and slower in laps 1 (P = .03; moderate effect) and 2 (P > .001; moderate effect). There were also greater variations of pace in the 1500-m running medalist group than in the nonmedalist group, with a relatively faster final lap (P = .03; moderate effect) and slower second lap (P = .01; small effect). Swimming gold medalists were relatively faster than all other finalists in lap 4 (P = .04), and running gold medalists were relatively faster than the 5th- to 12th-placed athletes in the final lap (P = .02).Conclusions:Athletes who win medals in 1500-m running and 400-m swimming competitions show different pacing patterns than nonmedalists. End-spurtspeed increases are greater with medalists, who demonstrate a slower relative speed in the early part of races but a faster speed during the final part of races than nonmedalists.

Despite females consistently reporting greater social physique anxiety (SPA), previous literature has yet to demonstrate whether SPA gender differences are linked to the way males and females perform physical activity. This study investigated an association between SPA and physical activity frequency, history of exercise, and physical activity intensity. Participants were represented by currently active users (N = 33 males; N = 31 females) of an on-campus university-run gym and completed a background physical activity questionnaire and the nine-item Social Physique Anxiety Scale. Participants also performed an exercise session at a self-selected level of exertion, with the intensity of each session measured via heart rate monitor. SPA was not associated with physical activity frequency, history of exercise (length of gym membership), or intensity for male and female exercisers. With respect to male participants, females reported higher SPA and a preference for performing higher intensity physical activity. Females and males also indicated a preference for performing aerobic and anaerobic physical activity respectively. Our findings suggest the experience of SPA does not deter body-conscious individuals from the performance of regular physical activity. Findings also suggest the discrepancy in male and female SPA is not linked to differences in the way physical activity is performed.

AimTo report an evaluation of health professionals’ participation in a distance-learning physical activity training course developed in a low socio-economic region of São Paulo city, Brazil.BackgroundIn countries with public universal health systems, physical activity promotion in primary health care settings can reap results, particularly given that such interventions have the potential to reach a large percentage of the population. However, few studies proposed physical activity training for health professionals in low- and middle-income countries. Brazil is a continental country and has the Unified Health System which incorporates family health teams in over 85% of Brazilian cities.MethodsThe physical activity training was part of the fifth module of an educational intervention throughout a distance-learning course focusing on health professionals at M’Boi Mirim district in São Paulo city. The training totaled 3 h and had five themes of physical activity: (1) concepts, definitions benefits; (2) evaluation; (3) recommendation; (4) interventions; (5) physical activity counseling. The opinion of health professionals was evaluated after training by two open questions.FindingsOut of 106 professionals who took part of the course, only 22.6% (n=24) had accessed the fifth module. These professionals were predominantly female (79.2%), nurses (66.7%) and aged 30 years or older. Responses highlighted the course approach focused on physical activity for improving patient’s quality of life and well-being, disease prevention and health improvements. Regarding the themes for improvement, the health professionals identified that there was a need to experience physical activity classes first-hand, and the need to link physical activity counseling to the local venues that provide structured physical activity programs. We recommend that further training courses can be conducted based on this model for health professionals to promote physical activity to the community in Brazil.

Item does not contain fulltext Background: Translational research is required to ensure exercise referral schemes (ERSs) are evidence-based and reflect local needs. This article reports process data from the co-development phase of an ERS, providing an insight into (i) factors that must be considered when translating evidence to practice in an ERS setting, and (ii) challenges and facilitators of conducting participatory research involving multiple stakeholders. Methods: An ERS was iteratively co-developed by a multidisciplinary stakeholder group (commissioners, managers, practitioners, patients and academics) via five participatory meetings and an online survey. Audio data (e.g. group discussions) and visual data (e.g. whiteboard notes) were recorded and analysed using NVivo-10 electronic software. Results: Factors to consider when translating evidence to practice in an ERS setting included (i) current ERS culture; (ii) skills, safety and accountability; and (iii) resources and capacity. The co-development process was facilitated by needs-analysis, open questions, multidisciplinary debate and reflective practice. Challenges included contrasting views, irregular attendance and (mis)perceptions of evaluation. Conclusion: The multidisciplinary co-development process highlighted cultural and pragmatic issues related to exercise referral provision, resulting in an evidence-based intervention framework designed to be implemented within existing infrastructures. Further work is required to establish the feasibility and effectiveness of the co-developed intervention in practice.

This study examined whether beetroot juice (BTJ) would attenuate inflammation and muscle damage following a marathon. Using a double blind, independent group design, 34 runners (each having completed ca. ∼16 previous marathons) consumed either BTJ or an isocaloric placebo (PLA) for 3 days following a marathon. Maximal isometric voluntary contractions (MIVC), countermovement jumps (CMJ), muscle soreness, serum cytokines, leucocytosis, creatine kinase (CK), high sensitivity C-reactive protein (hs-CRP), and aspartate aminotransferase (AST) were measured pre, post, and 2 days after the marathon. CMJ and MIVC were reduced after the marathon (P < 0.05), but no group differences were observed (P > 0.05). Muscle soreness was increased in the day after the marathon (BTJ; 45 ± 48 vs. PLA; 46 ± 39 mm) and had returned to baseline by day 2, irrespective of supplementation (P = 0.694). Cytokines (interleukin-6; IL-6, interleukin-8, tumour necrosis factor-α) were increased immediately post-marathon but apart from IL-6 had returned to baseline values by day 1 post. No interaction effects were evident for IL-6 (P = 0.213). Leucocytes increased 1.7-fold after the race and remained elevated 2 days post, irrespective of supplement (P < 0.0001). CK peaked at 1 day post marathon (BTJ: 965 ± 967, and PLA: 1141 ± 979 IU·L−1) and like AST and hs-CRP, was still elevated 2 days after the marathon (P < 0.05); however, no group differences were present for these variables. Beetroot juice did not attenuate inflammation or reduce muscle damage following a marathon, possibly because most of these indices were not markedly different from baseline values in the days after the marathon.

Neuroimaging methods have recently been used to investigate plasticity-induced changes in brain structure. However, little is known about the dynamic interactions between different brain regions after extensive coordinated motor learning such as drumming. In this article, we have compared the resting-state functional connectivity (rs-FC) in 15 novice healthy participants before and after a course of drumming (30-min drumming sessions, 3 days a week for 8 weeks) and 16 age-matched novice comparison participants. To identify brain regions showing significant FC differences before and after drumming, without a priori regions of interest, a multivariate pattern analysis was performed. Drum training was associated with an increased FC between the posterior part of bilateral superior temporal gyri (pSTG) and the rest of the brain (i.e., all other voxels). These regions were then used to perform seed-to-voxel analysis. The pSTG presented an increased FC with the premotor and motor regions, the right parietal lobe and a decreased FC with the cerebellum. Perspectives and the potential for rehabilitation treatments with exercise-based intervention to overcome impairments due to brain diseases are also discussed.

Background:The specific circumstances and contexts that may affect overweight and obese children’s participation in physical activity have thus far been given little attention. The qualitative study discussed in this paper explores the experiences of overweight and obese children and young people who have successfully increased their activity levels.Methods:The study sample was recruited from a community health and fitness scheme for children aged 5 to 16, with a Body Mass Index (BMI) at or above the 91st centile. Semistructured interviews were conducted with 58 children and young people. Data were analyzed using template analysis.Results:The children increased their feelings of capability to undertake physical activity, both while on the scheme and in other physical activity settings. They valued the range of ‘noncompetitive’ activities available and the nonthreatening atmosphere created. The ‘emotional’ support offered by the instructors was perceived as being integral to their enjoyment and continued participation.Conclusions:Physical activity providers need to be able to generate opportunities which allow children of any weight status to participate without fear of stigmatization or bullying. The findings of the current study suggest that to be effective what we should be focusing on is improving the physical activity experience from the child’s perspective.

Dietary inorganic nitrate supplementation causes physiological effects which may enhance exercise tolerance. However it is not known whether nitrate might alter cognitive function during exercise. In a double-blind, cross-over study, sixteen subjects ingested either nitrate-rich beetroot juice or a placebo and completed a continuous cycle exercise test involving 20min stages at 50% and 70% V˙O2peak and a final stage at 90% V˙O2peak until volitional exhaustion. Cognitive tasks were completed before, during and after exercise. In the dietary nitrate condition: plasma [nitrite] increased (p

Purpose: The purpose of this study was to investigate the influence of exercise intensity on postexercise supine and tilt baroreflex sensitivity (BRS). Method: Nine healthy, active men performed 2 conditions of interval cycling of 40% maximal work rate (WRmax) and 75% WRmax of matched work done and a control condition of no exercise in a counterbalanced order. BRS outcome measures were determined at preexercise and postexercise up to +24 hr in supine and tilt positions. R-R interval and blood pressure data were collected over consecutive 10-min periods and were analyzed by Fast Fourier transformation analysis. Results: A fully repeated analysis of variance revealed a significant interaction (p < .05) between time and condition in supine for BRSαLF, F(3, 134) = 5.19, p < .05, ES = .39, and BRSTFTG, F(3, 134) = 5.65, p < .05, ES = .41, and in tilt for BRSUpUp, F(3, 134) = 3.54, p < .05, ES = .31, BRSDownDown, F(3, 134) = 5.94, p < .05, ES = .43, BRSαLF, F(4, 134) = 6.23, p < .05, ES = .44, and BRSTFTG, F(4, 134) = 9.22, p < .05, ES = .54. There were significant differences (p < .05) between condition comparisons at +15 min and between control and 75% WRmax and between the 40% WRmax and 75% WRmax conditions at +60 min. At +15 min, BRS was lower in the 75% WRmax condition compared with the 40% WRmax condition and the control condition, and it was lower in the 40% WRmax condition than in the control condition. Conclusion: The findings demonstrate an intensity-dependent relationship in the BRS response following exercise.

No studies have analysed the acute effects of the FIFA 11+ and Harmoknee warm-up programmes on major physical performance measures. The aim of this study was to analyse the acute (post-exercise) effects of the FIFA 11+, Harmoknee and dynamic warm-up routines on several physical performance measures in amateur football players. A randomized, crossover and counterbalanced study design was used to address the purpose of this study. A total of sixteen amateur football players completed the following protocols in a randomized order on separate days: a) FIFA 11+; b) Harmoknee; and c) dynamic warm-up (DWU). In each experimental session, 19 physical performance measures (joint range of motion, hamstring to quadriceps [H/Q] strength ratios, dynamic postural control, 10 and 20 m sprint times, jump height and reactive strength index) were assessed. Measures were compared via a magnitude-based inference analysis. The results of this study showed no main effects between paired comparisons (FIFA 11+ vs. DWU, Harmoknee vs. DWU and Harmoknee vs. FIFA 11+) for joint range of motions, dynamic postural control, H/Q ratios, jumping height and reactive strength index measures. However, significant main effects (likely effects with a probability of >75- 99%) were found for 10 (1.7%) and 20 (2.4%) m sprint times, demonstrating that both the FIFA 11+ and Harmoknee resulted in slower sprint times in comparison with the DWU. Therefore, neither the FIFA 11+ nor the Harmoknee routines appear to be preferable to dynamic warm-up routines currently performed by most football players prior to training sessions and matches.

Research suggests that experiencing a moderate number of adverse life events can benefit future stress responses. This study explored the relationship between adverse life (ie, non-sport) events and cardiovascular responses to, and performance during, a pressurized sporting task. One hundred participants (64 men, 36 women; Mage=21.94 years, SDage=4.98) reported the number of adverse life events (eg, serious accident or injury) they had encountered before completing a pressurized dart-throwing task during which performance was recorded. Before the task, participants' demand and resource evaluations and cardiovascular reactivity were assessed. Adverse life events did not impact demand and resource evaluations. However, participants who reported 4-7 adverse life events displayed cardiovascular responses more reflective of a challenge state (relatively lower total peripheral resistance and/or higher cardiac output) compared to those who reported a lower (7) number of events. Furthermore, participants who reported 3-13 adverse life events outperformed those who reported a lower (13) number of events. Supplementary analyses suggested that this relationship might be due to a small number of extreme values. However, after outlier analyses, a significant linear relationship remained suggesting that a higher number of adverse life events facilitated performance. The results suggest that experiencing a moderate to high number of adverse life events might have beneficial effects on subsequent cardiovascular responses and performance under pressure. Practitioners should therefore consider prior brushes with adversity when identifying athletes who are likely to excel during stressful competition.

This study investigated the efficacy of deadlifts and box squats, with a combination of traditional and accommodating resistance, as a postactivation potentiating stimulus of standing broad jumps (SBJ) in a multiple-set contrast protocol. Twelve professional rugby league players (21.4 [2.5] y; 181.3 [8.3] cm, 91.9 [8.8] kg; 1-repetition-maximum [1RM] back squat/body mass 1.59 [0.21]; 1RM deadlift/body mass 2.11 [0.25]; ≥3-y resistance-training experience) performed baseline SBJ before a contrast postactivation potentiating protocol involving 2 repetitions of 85% 1RM box squat or deadlifts, loaded with a combination of traditional barbell weight (70% 1RM) and elastic-band resistance (∼15% 1RM), followed by 2 SBJs. Exercises were separated by 90 s, and 4 contrast pairs were performed in total. Using a repeated-measures design, all subjects performed the squat followed by the deadlift and finally the control (SBJ only) condition in the same order across consecutive weeks. Changes from baseline in SBJ distance were moderate for the box squat (effect size [ES] = 0.64–1.03) and deadlift (ES = 0.80–0.96) and trivial in the control condition (ES = 0.02–0.11). The magnitude of differences in postactivation potentiating effect were considered moderate (d = 0.61) for set 1, trivial for set 2 (d = 0.10) and set 3 (d = 0.05) in favor of box squats, and moderate for set 4 (d = 0.58) in favor of deadlifts. Accommodating resistance in either box squats or deadlifts is an effective means of potentiating SBJ performance across multiple sets of a contrast protocol with only 90-s rest.

Hughes, JD, Massiah, RG, and Clarke, RD. The potentiating effect of an accentuated eccentric load on countermovement jump performance. J Strength Cond Res 30(12): 3450-3455, 2016-Postactivation potentiation (PAP) following a bout of high-intensity exercise of short duration is known to produce both a fatigued and a potentiated state. There has been much research in the effectiveness of various PAP protocols, yet the type of dynamic muscle action utilized has seldom been investigated. Therefore, the present study aimed to assess whether an accentuated eccentric load (AE) could enhance subsequent performance. Eleven men (21 ± 2 years, 179.1 ± 6.9 cm, 83.2 ± 10.1 kg) performed 3 countermovement jumps (CMJs) before and 6 minutes after an AE and a back squat (BSq) PAP protocol. The participant's maximum CMJ height (cm) was determined before and after both protocol. A 2-way repeated measures analysis of variance was conducted to evaluate the effect of PAP condition and time on vertical jumping performance. A significant condition × time interaction was found (p = 0.02). Post hoc tests revealed that AE PAP had a significant (p = 0.03) potentiating effect on CMJ jump height. Whereas, the BSq PAP revealed no significant differences (p = 0.32). In conclusion, this study has shown that jump performance can be enhanced by eccentric muscle action when compared with a traditional BSq PAP protocol. This may provide a more practical method for coaches to enhance short-term explosive movements in athletic populations.