Vertical Strength Transfer Phenomenon Between Upper Body and Lower Body Exercise: Systematic Scoping Review.

BACKGROUND: There are a myriad of exercise variations in which upper body (UB) and lower body (LB) exercises have been intermittently used. However, it is still unclear how training of one body region (e.g. LB) affects adaptations in distant body areas (e.g. UB), and how different UB and LB exercise configurations could help facilitate physiological adaptations of either region; both referred to in this review as vertical strength transfer. OBJECTIVE: We aimed to investigate the existence of the vertical strength transfer phenomenon as a response to various UB and LB exercise configurations and to identify potential mechanisms underpinning its occurrence. METHODS: A systematic search using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) for Scoping Reviews protocol was conducted in February 2024 using four databases (Web of Science, MEDLINE, Scopus and CINAHL) to identify peer-reviewed articles that investigated the vertical strength transfer phenomenon. RESULTS: Of the 5242 identified articles, 24 studies met the inclusion criteria. Findings suggest that the addition of UB strength training to LB endurance exercise may help preserve power-generating capacity for the leg muscle fibres. Furthermore, systemic endocrine responses to high-volume resistance exercise may beneficially modulate adaptations in precedingly or subsequently trained muscles from a different body region, augmenting their strength gains. Last, strength training for LB could result in improved strength of untrained UB, likely due to the increased central neural drive. CONCLUSIONS: Vertical strength transfer existence is enabled by neurophysiological mechanisms. Future research should involve athletic populations, examining the potential of vertical strength transfer to facilitate athletic performance and preserve strength in injured extremities.

Physical match demands across different playing positions during transitional play and high-pressure activities in elite soccer.

This study explored physical match demands across different playing positions during transitional play, to inform the need for position-specific training interventions. Data was collected using 10 Hz GPS units from 10 competitive matches including 23 elite soccer players of the 1st Polish Division (Ekstraklasa) in season 2020-21. A total of 4249 positional observations were made; center backs (n = 884), full backs (n = 972), central defensive midfielders (n = 236), central attacking midfielders (n = 270), central midfielders (n = 578), wingers (n = 778), and attackers (n = 531). Match data reflected distances covered per minute (m · min-1): total distance (TD), high-speed running distance (HSRD, > 19.8 km · h-1), sprint distance (SD, > 25.2 km · h-1), and the frequency of high-intensity accelerations and decelerations (A+D, > 3 m · s-2; n · min-1). Total absolute sprint distance (SD, > 25.2 km · h-1) and total relative sprint distance (Rel B5) were also quantified. A univariate analysis of variance revealed position-specific differences. Significant effects of position were found for all analysed metrics during transitional play (large ESs; p <.001). Central attacking midfielders displayed higher TD (m · min-1), fullbacks covered highest SD (m · min-1) and wingers achieved the highest A+D (n · min-1) (p ≤ 0.05). Centre backs displayed the lowest physical outputs when compared to all other positions, except in A+D (n · min-1) during defensive transitions (p ≤ 0.05). Attackers displayed the highest physical metrics during high pressure activities (p ≤ 0.05). Coaches should carefully consider positional transitional demands to better inform training design. With specific attention paid to drills that replicate game play.

Worst Case Scenarios in Soccer Training and Competition: Analysis of Playing Position, Congested Periods, and Substitutes.

Aim: To understand mean (WCSmean) and peak (WCSpeak) worst case scenarios within training and game play in male professional soccer. Methods: Thirty-one (n = 31) first team players were monitored across 37 matches and 14 MD-3 sessions. Playing status was distinguished, football drills analyzed, and performance explored in long-period: >6 days, moderate-period: 5-6 days, and congested-period: ≤4 days. Relative total distance (TD), high-speed running distance (HSRD, >19.8 km·h-1), sprint distance (SD, >25.2 km·h-1), accelerations/decelerations (A+D, >3 m·s-2), accelerations (Acc, >3 m·s-2), and decelerations (Dec, >-3 m·s-2) were measured as well as Maximum acceleration (Max Acc; m·s-2) and deceleration (Max Dec; m·s-2). Results: Analysis of variance found differences between matches and training in WCSmean for TD, HSRD, SD, and Max Dec in all positions (p < .001; partial η2 > .275). Fullbacks displayed differences between match and training in Max Acc (moderate ESs; p < .001), while center backs and central midfielders in Max Dec (large ESs; p > .05). Main effects of playing status were discovered for all metrics except Max Dec (p < .001; partial η2 > .124). Analysis showed differences between long- and congested-period for A+D and Dec (large ESs; p ≤ .05). Conclusions: Findings provide more insights into short peak intensity demands of soccer showing that the maximum high velocity action of acceleration and deceleration is not being replicated in training. Nonstarters lack maximum intensity exposure in matches (WCSpeak) increasing the gap between training and competition even higher during congested fixture periods.

Towards an Evidence-Based Classification System for Para Dressage: Associations between Impairment and Performance Measures.

This study follows a previously defined framework to investigate the impact of impairment on performance in Para dressage athletes. Twenty-one elite Para dressage athletes (grades I to V) and eleven non-disabled dressage athletes (competing at Prix St. Georges or Grand Prix) participated. Data were collected in two phases: performing a two minute custom dressage test on a riding simulator while kinematic data were synchronously collected using inertial measurement units (2000 Hz) and optical motion capture (100 Hz), and clinically assessed using a battery of impairment assessment tools administered by qualified therapists. Impairment and performance measures were compared between Para and non-disabled athletes. Significant differences between athlete groups were found for all impairment measures and two performance measures: simulator trunk harmonics (p = 0.027) and athlete trunk dynamic symmetry (p < 0.001). Impairment assessments of sitting function and muscle tone could predict 19 to 35% of the impact of impairment on performance in Para athletes but not in non-disabled athletes. These findings provide the basis for a robust, scientific evidence base, which can be used to aid in the refinement of the current classification system for Para dressage, to ensure that it is in line with the International Paralympic Committee's mandate for evidence-based systems of classification.

Methods of Measuring Laryngeal Muscle Tension in Patients with Muscle Tension Dysphonia: A Scoping Review.

BACKGROUND: In clinical practice and research relating to Muscle Tension Dysphonia (MTD), several laryngeal muscle tension measurement methods are used to diagnose, to identify specific muscle strengths and deficits, and to measure therapeutic outcomes. The variety and reliability of available measurement methods presents challenges within diagnosis and treatment. The lack of methodical standardization presents a barrier to homogeneous practice in this area. There is a need for a comprehensive scoping review of laryngeal muscle tension measurement methods. STUDY DESIGN: Scoping review. OBJECTIVES: (1) To identify current methods of laryngeal muscle measurement which have been developed or tested with people with MTD; and (2) To identify the construct/s measured, reliability, validity, ability to detect change, efficiency and accessibility of identified methods. METHOD: This scoping review was conducted using the Arksey and O'Malley framework. Studies were identified through searches of 4 major databases. The reviewer independently assessed titles, abstracts, and full-text articles. RESULTS: Twenty seven papers published from 2000 to 2022 that satisfied the inclusion criteria were selected from 194 studies. The papers showed a variety of approaches with regards to the measurement of laryngeal activity and tension in subjects with MTD. Just over a quarter (25.9%) were reviews of the validity of assessment methods of MTD, including surface electromyography (sEMG), while 22.2% discussed surface electromyography as a measurement of muscle activity in subjects with MTD. 96.3% used a published methodological framework. CONCLUSIONS: Assessment methods for Primary MTD are multifaceted, including patient history, laryngoscopic examination, and voice-related musculoskeletal features. Potential use of objective measurement methods, including sEMG, Real Time Elastosonography, Magnetic Resonance Imaging was noted. Due to variability in assessment methods and results, there is a need for greater objective practical methodological standardization to ensure accurate diagnosis, appropriate care, and chart patient progress.

Test-Retest Reliability of the Isometric Soleus Strength Test in Elite Male Academy Footballers.

BACKGROUND: Currently there is no reliability data available for the isometric soleus strength test (ISST), commonly used as a monitoring tool in elite football settings. Isometric strength testing for other muscle groups, most notably the hamstrings, is utilized to identify injury risk and readiness to train/play. To profile athletes efficiently, performance practitioners require optimal measures that are reliable. The aim of this study was to investigate the test-retest reliability of the isometric strength test of the soleus and propose a standardized protocol for its use within an elite male football population. STUDY DESIGN: Test-retest reliability single cohort study. METHODS: Thirty elite male footballers (age = 22.8±5.0 years, height = 180.0±0.08 cm, weight = 70.57±4.0 kg) performed the ISST, through three maximum 3-second hold efforts with one minute rest between repetitions and 48 hours between tests, in each test. The test was performed mid-competitive season. All data bilaterally were checked for normality using the Shapiro-Wilk test before a Pearson's Correlations and Bland-Altman's analyses were performed. RESULTS: Test-retest reliability demonstrated high reliability for ISST bilaterally (Right: r = 0.89; Left: r = 0.79, p<0.05). The standard error of measurement (SEM) (%) was 9.09 - 12.47% and minimal detectable change (MDC) was 25.19 - 34.56 (N) for Peak Force (PF) measures of the ISST. Bilateral levels of agreement were found to be +/- 2 standard deviations (SD) of the interval of agreement bilaterally for ISST (Levels of agreement (LOA): Right: Upper 352.49 - Lower -494.76; Left: Upper 523.82 - Lower -591.30. Bilaterally no significant difference was detected between values (Right: p=0.09, CI: -153.21-10.95; Left: p=0.52, CI: -139.81-72.33). CONCLUSION: The results of this study demonstrate high reliability for the ISST. The ISST displays a high test-retest reliability for assessing PF characteristics of the soleus in elite male academy footballers. This test may be beneficial for performance practitioners for profiling soleus function of athletes.

Cold for centuries: a brief history of cryotherapies to improve health, injury and post-exercise recovery.

For centuries, cold temperatures have been used by humans for therapeutic, health and sporting recovery purposes. This application of cold for therapeutic purposes is regularly referred to as cryotherapy. Cryotherapies including ice, cold-water and cold air have been popularised by an ability to remove heat, reduce core and tissue temperatures, and alter blood flow in humans. The resulting downstream effects upon human physiologies providing benefits that include a reduced perception of pain, or analgesia, and an improved sensation of well-being. Ultimately, such benefits have been translated into therapies that may assist in improving post-exercise recovery, with further investigations assessing the role that cryotherapies can play in attenuating the ensuing post-exercise inflammatory response. Whilst considerable progress has been made in our understanding of the mechanistic changes associated with adopting cryotherapies, research focus tends to look towards the future rather than to the past. It has been suggested that this might be due to the notion of progress being defined as change over time from lower to higher states of knowledge. However, a historical perspective, studying a subject in light of its earliest phase and subsequent evolution, could help sharpen one's vision of the present; helping to generate new research questions as well as look at old questions in new ways. Therefore, the aim of this brief historical perspective is to highlight the origins of the many arms of this popular recovery and treatment technique, whilst further assessing the changing face of cryotherapy. We conclude by discussing what lies ahead in the future for cold-application techniques.

Utilisation of performance markers to establish the effectiveness of cold-water immersion as a recovery modality in elite football.

Optimal strategies for recovery following training and competition in elite athletes presents ongoing debate. The effects of cold-water immersion (CWI) compared to passive recovery (PR) though a triad of performance measures after fatiguing exercise within a normal micro-cycle, during mid-competitive training cycle, in elite male footballers were investigated. Twenty-four elite footballers (age 20.58 ± 2.55 years; height 179.9 ± 5.6 cm; weight 75.7 ± 7.5 kg; body fat 6.2 ± 1.7%) were randomly assigned to CWI or PR following a fatiguing training session. Objective measures included eccentric hamstring strength, isometric adductor strength, hamstring flexibility and skin surface temperature (T sk ). Subjective measures included overall wellbeing. Data were collected at match day+3, immediately post-training, immediately post-intervention and 24 hrs post-intervention. Physiological, biomechanical and psychological measures displayed significant main effects for timepoint for eccentric hamstring strength, T sk , overall wellbeing, sleep, fatigue, stress and group for eccentric hamstring strength, T sk and sleep (groups combined). Group responses identified significant effects for timepoint for CWI and PR, for eccentric hamstring strength peak force, sleep, fatigue, and muscle soreness for CWI. Significant differences were displayed for eccentric hamstring strength (immediately post-intervention and immediately post-training) for peak force and between CWI and PR eccentric hamstring strength immediately post-intervention. Linear regression for individual analysis demonstrated greater recovery in peak torque and force for CWI. CWI may be useful to ameliorate potential deficits in eccentric hamstring strength that optimise readiness to train/play in elite football settings. Multiple measures and individual analysis of recovery responses provides sports medicine and performance practitioners with direction on the application of modified approaches to recovery strategies, within mid-competitive season training cycles.

Effects of contemporary cryo-compression on post-training performance in elite academy footballers.

Fatigue is a predisposing risk factor for injury commonly investigated in elite football populations. Little evidence advocates the most beneficial recovery strategies including contemporary cooling applications. The aim of the study was to examine immediate effects of the Game Ready® on physiological and biomechanical measures in a population of elite male academy footballers, following a fatiguing training session mid-competitive season. Twenty, elite male footballers took part (180.2 ± 8.7cm, 75.0 ± 11.4kg, 18 ± 0.5years). Following a normal fatiguing training session, players were randomly assigned to receive either cryotherapy (Game Ready®) (20-minutes at medium compression (5-55 mm Hg)) or passive recovery (PAS). Data was collected at match-day+1, immediately post-training and immediately post-intervention. Performance measures included countermovement jump (CMJ), isometric adductor strength (IAS), hamstring flexibility (HF), and skin surface temperature (Tsk). Significant main effects for group for CMJ data following exposure to cooling were displayed (p = < 0.05). Individual group analysis displayed a significant reduction in CMJ performance in the group exposed to cryotherapy (p = < 0.05) immediately post, but not for PAS. No main effects were identified for cryotherapy or PAS group for IAS or HF (p = > 0.05). Tsk reduced significantly (p = < 0.05) in the cryotherapy group, meeting therapeutic Tsk range. Reductions in performance immediately following exposure to pneumatic cryo-compressive devices may negate the justification of this recovery strategy if neuromuscular mechanisms are required in immediate short term. Application of such recovery strategies however are dependent on the type of recovery demand and should be adapted individually to suit the needs of the athlete to optimise readiness to train/play.

Cryotherapy in sport: a warm reception for the translation of evidence into applied practice.

Research contributing to the understanding of the mechanisms that underpin cryotherapy application in sport are evident. The translation of impactful findings that contribute to the design and implementation of cryotherapy protocols which are advantageous to the athlete in an applied sport setting, however, are still being explored. The role of cryotherapy for acute sport injury management is challenged in recent literature and discrepancies around the periodisation of cooling to maximise injury management or recovery, contribute to the confusion around optimal applications of cryotherapy in sport. The purpose of this work was to provide a contemporary summary of current perspectives, challenges and approaches for the use, application and translation of cryotherapy evidence into applied practice in a sporting context. The intention being to stimulate further debate on the topic and highlight key considerations for future study designs that reflect current practices. For improved translation of evidence for or against the use of cryotherapy in sport, it is suggested that future study design and methodologies should reflect contemporary demands within sporting environments where cryotherapy protocols for injury, rehabilitation or recovery are a feature of athlete management through investigation of individual response, and multi-measures of wellbeing and performance.

Rider Skill Affects Time and Frequency Domain Postural Variables When Performing Shoulder-in.

In equestrian sports the novice rider learns first to follow the movements of the horse's back and then how to influence the horse's performance. One of the rider's challenges is to overcome inherent horse and/or rider asymmetry patterns when riding in straight lines, mirroring the movements on the left, and right sides when turning. This study compares the performance of novice and advanced riders when riding in sitting trot on straight lines and when riding shoulder-in to the left and right sides. Eight novice and eight advanced horse-rider combinations performed sitting trot in a straight line, shoulder-in left and shoulder-in right while wearing a full body set of inertial sensors. An experienced dressage judge indicated when the movements were being performed correctly and assigned scores on a scale of 0-10 for the quality of performance. Kinematic data from the inertial sensors were analyzed in time and frequency domain. Comparisons were made between trotting on the straight, shoulder-in left, and shoulder-in right. Advanced riders received higher dressage scores on all three movements, but significantly (P < .05) lower scores were found for shoulder-in right across the two groups. When riding shoulder-in, advanced riders had greater hip extension (advanced = -5.8 ± 17.7; novice = 7.8 ± 8.9 degrees) and external rotation (advanced = -32.4 ± 15.5; novice = -10.8 ± 13.2 degrees) in the outside leg compared with novices (P < .05), which reflects an important cue in achieving the required body rotation in the horse. Lower scores for shoulder-in right may be linked to significant (P < .05) changes in harmonics of trunk to pelvis rotation.

The Effect of Local Cooling at the Elbow on Nerve Conduction Velocity and Motor Unit Behaviour: An Exploration of a Novel Neurological Assessment.

BACKGROUND: This study aimed to determine the effects of a standard therapeutic cooling protocol using crushed ice on the elbow to explore if changes in the motor unit (MU) firing rates in the first dorsal interosseous (FDI) muscle are comparable to known changes in sensory and motor nerve conduction velocity (NCV) due to a regional temperature drop around a peripheral nerve. METHODS: Twelve healthy individuals were assessed before cooling, immediately after cooling, and 15 min of rewarming. Assessments included two standard non-invasive nerve conduction velocity tests and a non-invasive investigation of the MU firing rates using surface electromyography decomposition (dEMG). RESULTS: Repeated ANOVAs showed significant differences in the MU firing rates and NCV between time points (p = 0.01 and p < 0.001). All measures showed significant differences between pre and post cooling and between pre-cooling and 15 min of passive re-warming, however, no changes were seen between post cooling and rewarming except in the sensory NCV, which increased but did not return to the pre-cooled state. CONCLUSIONS: This current study showed a significant, temporary, and reversible reduction in ulnar NCV across the elbow in healthy subjects, which was associated with a significant decrease in mean MU firing rates in the FDI muscle.

The Effect of High-Intensity Accelerations and Decelerations on Match Outcome of an Elite English League Two Football Team.

OBJECTIVES: Previous research has highlighted the frequency of high-intensity accelerations and decelerations in elite football. The influence of these actions on match performance outcomes has not been established. The aim of the present study was to identify the influence of high-intensity accelerations and decelerations on match performance outcomes (i.e., win, draw, lost). Comparisons were also made between team and positional high-intensity accelerations and decelerations recorded within the games. METHODS: 26 elite outfield footballers from an elite English Football League (EFL) Two team completed the present study. Global Positioning System (GPS) technology was utilised to quantify high-intensity accelerations and decelerations during 45 games in a competitive season. Magnitude analysis and the effects of results, positions and fixture periods were observed. RESULTS: Significant effects of results, periods and positions were observed (p ≤ 0.05), with the highest outputs observed in games won. Positionally, fullbacks and centre forwards in a 4-3-3 formation exhibited the greatest frequency of high-intensity accelerations and decelerations. Very large differences were observed between the frequency of high-intensity decelerations compared to accelerations in games won (g = 2.37), drawn (g = 2.99) and lost (g = 3.59). The highest team frequencies of high-intensity accelerations (n = 3330) and decelerations (n = 6482) were completed in games won. CONCLUSIONS: The frequency of high-intensity accelerations and decelerations has a significant impact on match performance outcomes in an elite English League Two football team. Consideration needs to be given to specific conditioning and recovery strategies to optimise high-intensity acceleration and deceleration performance in games. Caution should be taken as these findings are representative of one team within the EFL.

The Temporal Pattern of Recovery in Directional Dynamic Stability Post Football-Specific Fatigue.

BACKGROUND: Rising injury rates within football require further understanding of the etiological risk factors associated with lower-limb injury. AIM: To examine the temporal pattern of recovery of directional dynamic stability measures post football-specific fatigue. METHODS: Eighteen male elite footballers completed baseline assessments of directional dynamic stability measures (Overall Stability Index, anterior-posterior stability [A-P], medial-lateral stability [M-L] on level 1 of the Biodex Stability System). Post Soccer-Specific Aerobic Field Test90 measures were repeated immediately, +24 hours, +48 hours, and +72 hours. The main effects for the recovery time and direction of stability were supplemented by regression modeling to describe the temporal pattern of recovery. RESULTS: Significant main effects for time were identified for all directions of stability (Overall Stability Index, A-P, and M-L) up to +48 hours postexercise (P ≤ .05). The quadratic pattern of temporal recovery highlights a minimum of 37.55 to 38.67 hours and maximum of 75.09 to 77.33 hours. Additionally, a main effect for direction of stability was observed, with significant differences identified between A-P and M-L stability at all time points (P ≤ .001). CONCLUSIONS: Reductions in directional dynamic stability +48 hours postfatigue highlight implications for training design, recovery strategies, and injury management for performance practitioners. Interestingly, A-P stability has been highlighted as being significantly reduced compared with M-L stability at all time points, regardless of the fatigue exposure. Practitioners should consider the reduction of stability in this plane in relation to common mechanisms of injury in the knee to inform injury-risk-reduction strategies.

The relationship between eccentric hamstring strength and dynamic stability in elite academy footballers.

OBJECTIVES: Previous research describes dynamic stability and functional strength as key aetiological risk factors associated with lower limb non-contact musculoskeletal injury. Due to the multifactorial nature of injury risk, relationships between the two factors will inform injury management and training design. METHODS: A total of 59 elite academy footballers from two English premier league category 1-status academies completed the study. All players completed measures of eccentric hamstring strength and dynamic stability. Relationships between directional stability (Anteroposterior (Ant), Posteromedial (PM) and Posterolateral (PL)) and eccentric strength metrics (PkT, AvT, PkF, AvF and Ɵ) bilaterally were identified for analysis. RESULTS: Significant correlations were identified bilaterally for functional hamstring strength metrics and PM and PL stability (P ≤. 0.05). No significant relationships were identified between anterior stability and eccentric hamstring strength parameters (P > 0.05). CONCLUSIONS: Eccentric hamstring strength has a positive influence on directional stability through two planes, PM and PL. The lack of influence of eccentric hamstring strength on Ant directional stability could be attributed to increased ACL risk. Careful consideration of the significance of the relationships between eccentric hamstring strength and directional stability must be given when quantifying injury risk in elite academy footballers.

The Effect of Proprioceptive Training on Directional Dynamic Stabilization.

OBJECTIVES: Significant loss of playing time and the impact of treatment costs due to lower limb injury in football demonstrates a need for improved protocols for injury risk reduction. The aim of the present study is to assess the effect of a proprioceptive training program on the lower limb dynamic stability of elite footballers. METHODS: A total of 16 elite premier league footballers were randomly allocated by matched pair design to a 8-week proprioception training group (group A, n = 8) or nontraining group (group B, n = 8), to determine the effect of this training over a 16-week period. Group A completed 8 weeks of bilateral proprioceptive training, 5 times per week for 10 minutes. The Biodex Stability System measures of overall stability index, anterior-posterior (A-P), and medial-lateral stability (M-L) at levels 8-6-4-1 were taken for both groups at baseline, 4, 8, and 16 weeks. Main effects of time, level of stability, and direction of stability were determined, with comparisons of effect made between the 2 groups. RESULTS: The training group displayed significant differences for multidirectional stability at week 8 (P ≤ .05). The A-P stability within the training group displayed significant differences between baseline measures and 16 weeks (P > .05), with significant increases in scores displayed for M-L and A-P stability between weeks 8 and 16 (P ≤ .05), representing a detraining effect. No significant differences were detected at any time point for the nontraining group (P > .05). CONCLUSIONS: Proprioceptive training over 8 weeks has a positive effect on all directions of stability. Greater declines in A-P stability were evident at 16 weeks when compared with M-L and overall stability index. Consideration must be given to the increased stability scores presented pretesting for A-P when compared with M-L. Findings of this work present implications for training design.

COMPARISON OF CRYOTHERAPY MODALITY APPLICATION OVER THE ANTERIOR THIGH ACROSS RUGBY UNION POSITIONS; A CROSSOVER RANDOMIZED CONTROLLED TRIAL.

BACKGROUND: In deliberation of the diverse physical traits of rugby union and the known interference adipose tissue has on the ability to cool deeper tissues, evidence is required to understand the effect of cryotherapy modalities to provide optimum outcomes post-injury. PURPOSE: To investigate differences in the cooling ability of three different cryotherapy modalities in a rugby union population in an attempt to describe optimum cooling protocols for the anterior thigh. STUDY DESIGN: Within-subjects randomized control crossover. METHODS: Twenty-one healthy male rugby union players took part. Skin surface temperature measured via thermal imaging camera (ThermoVision A40M, Flir Systems, Danderyd, Sweden) alongside Thermal Comfort and Sensation questionnaires following interventions of either Wetted Ice (WI), Crushed Ice (CI) applied in a polythene bag secured by plastic wrap, or CryoCuff® (CC), applied for 20-minutes over the anterior thigh. Participants were grouped by their typical playing position for the sport of rugby union; i.e. forwards and backs. RESULTS: Significant differences (p=<0.05) in T sk for all modalities compared to baseline and comparing post T sk between CI and CC (p=0.01) and WI to CC (p=0.01) were displayed. Significantly greater reductions in T sk noted immediately-post in the 'forwards' group (p=≤0.05) compared to the 'backs' group for, all modalities (p=≤0.05). Thermal Comfort and Sensation scores demonstrated significant changes baseline compared to post for all modalities (p=<0.05). No significant differences were found when comparing between modalities for Thermal Comfort (p=0.755) or Sensation (p=0.225) for whole group or between positional groups. CONCLUSIONS: Physiological responses to cooling differed across modalities with WI producing the greatest decrease in T sk. Significant variability in T sk was also displayed between positional factions. Results uphold the importance of the individualization of local cooling protocols when considering physical traits and characteristics within a rugby union population. Findings provide further understanding of the physiological responses to cooling through T sk quantification in specific populations, helping to guide sports medicine practitioners on optimal cooling application development in sport. LEVEL OF EVIDENCE: Level 2b.

Measures of PHV and the effect on directional dynamic stability to identify risk factors for injury in elite football.

BACKGROUND: The aim of this study is to analyze the relationship between peak height velocity (PHV) and dynamic balance (Y-Balance) versus non-peak growth to identify risk factors for non-contact lower limb injuries using a retrospective study design in elite youth footballers. METHODS: Ninety-three elite category 1 academy football players completed Y-Balance assessment during the preseason screening assessment. Data in relation to Y-Balance and Peak Height Velocity measures was than analyzed retrospectively and correlated against injury audit data to identify relationships between the variables. RESULTS: A significant correlation was identified between PHV and measures of directional dynamic stability utilizing Y-Balance assessment (P≤0.001). No significant correlations were identified between PHV and injury or injury and dynamic stability scores (P>0.05). Injury occurrence for players within predicted periods of PHV was represented as 45%, within the cohort contained within the study. CONCLUSIONS: Evidently periods of growth and maturation within elite academy footballers has a detrimental effect on directional dynamic stability performance. However, caution must be taken with interpreting the significance of this relationship and the effect it has on injury occurrence. Consideration must be given to quantifying key etiological factors associated with injury during adolescence and refrain from reliance on measures of PHV.

Temporal Patterns of Knee-Extensor Isokinetic Torque Strength in Male and Female Athletes Following Comparison of Anterior Thigh and Knee Cooling Over a Rewarming Period.

CONTEXT: The effect of local cooling on muscle strength presents conflicting debates, with literature undecided as to the potential implications for injury, when returning to play following cryotherapy application. OBJECTIVE: To investigate concentric muscle strength following local cooling over the anterior thigh compared with the knee joint in males and females and the temporal pattern over a 30-minute rewarming period. DESIGN: Repeated-measures crossover design. METHOD: Twelve healthy participants randomly assigned to receive cooling intervention on one location, directly over either the anterior thigh or the knee, returning 1 week later to receive the cooling intervention on opposite location. Muscle strength measured via an isokinetic dynamometer at multiple time points (immediately post, 10-, 20-, and 30-min post) coincided with measurement of skin surface temperature (Tsk) using a noninvasive infrared camera. RESULTS: Significant main effects for time (P ≤ .001, η2 = .126) with preice application higher than all other time points (P ≤ .05) were demonstrated for both peak torque and average torque. There were also significant main effects for isokinetic testing speed, sex of the participant, and position of the ice application for both peak torque and average torque (P ≤ .05). Statistically significant decreases in Tsk were reported in both gender groups across all time points compared with preintervention Tsk for the anterior thigh and knee (P < .05). CONCLUSIONS: Reductions reported for concentric peak torque and average torque knee-extensor strength in males and females did not fully recover to baseline measures at 30-minute postcryotherapy interventions. Sports medicine practitioners should consider strength deficits of the quadriceps after wetted ice applications, regardless of cooling location (joint/muscle) or gender.