ABSTRACT:Silvestri, MA, Cleather, DJ, Callaghan, S, Perri, J, and Legg, HS. Examining the determinants of skating speed in ice hockey athletes: a systematic review. J Strength Cond Res 39(4): 507-514, 2025-Ice hockey is a physically demanding sport that requires athletes to maintain high skating speed for optimal performance. This systematic review examines existing research on testing ice hockey athletes in relation to skating speed and identifies key metrics to inform future decisions on the most suitable testing regimes. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed for the literature search. After the literature search and application of inclusion and exclusion criteria, 19 studies were deemed eligible. The identified measures that showed a significant correlation with ice skating performance were on-land sprinting, jumping, body composition, and anaerobic power. These findings highlight the multifactorial nature of skating performance and suggest that a range of tests may be necessary to identify critical factors to overall skating performance; however, further research is needed to confirm this hypothesis.

Abstract An abundance of degrees of freedom (DOF) exist when executing a countermovement jump (CMJ). This research aims to simplify the understanding of this complex system by comparing jump performance and independent functional DOF (fDOF) present in CMJs without (CMJNoArms) and with (CMJArms) an arm swing. Principal component analysis was used on 39 muscle forces and 15 3-dimensional joint contact forces obtained from kinematic and kinetic data, analyzed in FreeBody (a segment-based musculoskeletal model). Jump performance was greater in CMJArms with the increased ground contact time resulting in higher external (p = .012), hip (p < .001) and ankle (p = .009) vertical impulses, and slower hip extension enhancing the proximal-to-distal joint extension strategy. This allowed the hip muscles to generate higher forces and greater time-normalized hip vertical impulse (p = .006). Three fDOF were found for the muscle forces and 3-dimensional joint contact forces during CMJNoArms, while four fDOF were present for CMJArms. This suggests that the underlying anatomy provides mechanical constraints during a CMJ, reducing the demand on the control system. The additional fDOF present in CMJArms suggests that the arms are not mechanically coupled with the lower extremity, resulting in additional variation within individual motor strategies.

High Frequency Impulse for Microgravity (HIFIm) is an exercise countermeasure that is designed to minimize force and vibration transmission to the spacecraft during exercise without the need for an additional VIS. The purpose of this study was to evaluate the effectiveness of HIFIm in mitigating force transmission in microgravity during parabolic flight. Force between HIFIm and the aircraft was measured using a custom-made arrangement of load cells during repeated jumping by two participants. Mean peak force transmission to the aircraft was 4.79 ± 0.68 N.kg− 1. In addition, the frequency spectra for the upper and lower fixations to the aircraft were within the envelope of what is permissible for an exercise countermeasure on Gateway. These data support the design concept of HIFIm and suggest that HIFIm could be installed in a space habitat with no, or minimal, additional VIS. Measuring the force and vibration transmission of exercise countermeasures in microgravity during parabolic flight is highly challenging due to the safety constraints of the experimental platform and the extreme changes in acceleration (from 0 to 1.8 g). The fact that this performance can be directly measured for HIFIm is a key advantage. The results presented here add to the mounting evidence that HIFIm is the future of exercise countermeasures.

Ballet class represents a considerable portion of professional ballet training, yet the external training load demands associated with class-and particularly the jumping demands-have not been investigated. The purpose of this study was to measure the jumping demands of ballet class by sex and rank. Eleven female and eight male elite professional ballet dancers participated in 109 ballet classes taught by 12 different teachers. Jump counts and jump heights were measured during each class. A Poisson generalized linear mixed effects model was used to examine the differences in jump counts between sexes and ranks. Greater jump counts were observed during class in men than in women (153, 95% confidence intervals [CI] [137, 170] vs. 119, 95% CI [109, 131], p = 0.004) and in junior ranking dancers compared with senior ranking dancers (151, 95% CI [138, 165] vs. 121, 95% CI [108, 135], p = 0.006). Female junior and senior ranking dancers jumped at rates of 9.2 ± 2.6 and 8.6 ± 4.7 jumps·min-1 , respectively, while male junior and senior ranking dancers jumped at rates of 9.1 ± 2.6 and 8.7 ± 2.6 jumps·min-1 , respectively. Across all classes, 73% of jumps observed were below 50% of maximum double-legged countermovement jump height. Unlike rehearsals and performances, class offers dancers an opportunity to self-regulate load, and as such, are a useful session to manage jump load, and facilitate gradual return-to-dance pathways. Communication between health care and artistic staff is essential to facilitate load management during class.

An abundance of degrees of freedom (DOF) exist when executing a countermovement jump (CMJ). This research aims to simplify the understanding of this complex system by comparing jump performance and independent functional DOF (fDOF) present in CMJs without (CMJ(NoArms)) and with (CMJ(Arms)) an arm swing. Principal component analysis was used on 39 muscle forces and 15 3-dimensional joint contact forces obtained from kinematic and kinetic data, analyzed in FreeBody (a segment-based musculoskeletal model). Jump performance was greater in CMJ(Arms) with the increased ground contact time resulting in higher external (p = 0.012), hip (p < 0.001) and ankle (p = 0.009) vertical impulses, and slower hip extension enhancing the proximal-to-distal joint extension strategy. This allowed the hip muscles to generate higher forces and greater time-normalized hip vertical impulse (p = 0.006). Three fDOF were found for the muscle forces and 3-dimensional joint contact forces during CMJ(NoArms), while four fDOF were present for CMJ(Arms). This suggests that the underlying anatomy provides mechanical constraints during a CMJ, reducing the demand on the control system. The additional fDOF present in CMJ(Arms) suggests that the arms are not mechanically coupled with the lower extremity, resulting in additional variation within individual motor strategies.

Repeated jumping has been demonstrated as a feasible exercise countermeasure in microgravity and has been shown to reduce deconditioning in head down bed rest studies. However, varying landing stiffness may provide greater contribution of both axial and medio-lateral bone strain and muscle loading at greater muscle lengths, which may help minimize bone and muscle deconditioning. Therefore, this study investigated the effect of different landing styles on the force profile and ground contact time during repeated jumping using HIFIm in microgravity. Two participants performed repeated jumping on the HIFIm jump sled in microgravity during a parabolic flight campaign. ‘Ground’ forces and ground contact time were compared between landing styles where increased landing stiffness was instructed to the jumper, and increased spring resistance. The results show that the forces experienced when performing repeated jumps in microgravity are sensitive to the landing style employed. As greater stiffness was instructed, peak forces increased, and ground contact time decreased significantly. Peak forces and ground contact time also significantly increased when spring resistance increased. These results highlight that landing instructions and spring configurations could be used as training variables when developing an astronaut training program, which can use different jump styles to minimize bone and muscle deconditioning. Further research using bed rest analogs and repeated jumping using HIFIm is needed to demonstrate varied repeated jumping interventions as an effective exercise method for minimizing deconditioning in astronauts.

Objective To elicit expert opinion and gain consensus on specific exercise intervention parameters to minimise hip bone mineral density (BMD) loss following traumatic lower limb amputation. Methods In three Delphi rounds, statements were presented to a panel of 13 experts from six countries. Experts were identified through publications or clinical expertise. Round 1 involved participants rating their agreement with 22 exercise prescription statements regarding BMD loss post amputation using a 5-point Likert scale. Agreement was deemed as 3–4 on the scale (agree/strongly agree). Statements of <50% agreement were excluded. Round 2 repeated remaining statements alongside round 1 feedback. Round 3 allowed reflection on round 2 responses considering group findings and the chance to change or maintain the resp onse. Round 3 statements reaching ≥70% agreement were defined as consensus. Results All 13 experts completed rounds 1, 2 and 3 (100% completion). Round 1 excluded 12 statements and added 1 statement (11 statements for rounds 2–3). Round 3 reached consensus on nine statements to guide future exercise interventions. Experts agreed that exercise interventions should be performed at least 2 days per week for a minimum of 6 months, including at least three different resistance exercises at an intensity of 8–12 repetitions. Interventions should include weight-bearing and multiplanar exercises, involve high-impact activities and be supervised initially. Conclusion This expert Delphi process achieved consensus on nine items related to exercise prescription to minimise hip BMD loss following traumatic lower limb amputation. These recommendations should be tested in future interventional trials.

Purpose: The aims of the present study were to: (1) investigate the magnitude and direction of the cross-education effect in a unilateral sport skill (overhand throw) and (2) to establish which practice condition (dominant hand only or alternating hands) would yield the best results. Methods: The study involved three experimental groups of 11-year-old children (n = 59). The first group (n = 20) used only the dominant hand to throw the ball. The second group (n = 19) used the nondominant hand only, while the third (n = 20) alternated hands for each throw. A pre- and post-testing of both hands preceded and followed the intervention period. Results: The results of our study revealed no asymmetry in cross-education effect between the limbs for children's overhand ball throwing. It was also shown that training both hands is superior to training the dominant hand alone. Conclusion: Our findings would be of particular interest to physical education teachers and coaches of unilateral sports who are advised to review their unilateral skill teaching methods as bilateral training offers a superior approach to augmenting the process of motor learning and performance.

Exercise countermeasures are a ubiquitous part of space habitation due to the need to mitigate the deconditioning effect of microgravity. However, exercise in space creates forces that need to be isolated from the habitat, and these so-called Vibration Isolation Systems (VIS) are typically large and heavy. High Frequency Impulse for Microgravity (HIFIm) is an exercise countermeasure that is designed to minimize force and vibration transmission to the spacecraft without the need for an additional VIS. The purpose of this study was to evaluate the effectiveness of HIFIm in mitigating force transmission in microgravity during parabolic flight. Force between HIFIm and the aircraft was measured using a custom-made arrangement of load cells during repeated jumping by two participants. Mean peak force transmission to the aircraft was 4.79 ± 0.68 N.kg-1. In addition, the frequency spectra for the upper and lower fixations to the aircraft were within the envelope of what is permissible for an exercise countermeasure on Gateway. These data support the design concept of HIFIm and suggest that HIFIm could be installed in a space habitat with no, or minimal, additional VIS. Measuring the force and vibration transmission of exercise countermeasures in microgravity during parabolic flight is highly challenging due to the safety constraints of the experimental platform and the extreme changes in acceleration (from 0-1.8g). The fact that this performance can be directly measured for HIFIm is a key advantage. The results presented here add to the mounting evidence that HIFIm is the future of exercise countermeasures.

INTRODUCTION:The aim of In this study was to verify the relationship among clinical indicators of patellofemoral pain syndrome (PFPS) and the results of modifying radiological investigation. Previous research suggests that there is a poor association between them. Therefore we have employed a technique for the functional evaluation of PFPS based on measuring the stiffness of the knee joint during passive flexion (biorheometry). METHOD:The correlation between clinical examination and a standardized Lysholm score, radiological and biorheometric measures was investigated in the 28 knee joints of 14 subjects exhibiting clinical features of PFPS. A modified axial radiological projection of the patellofemoral articulation in 90° of flexion provided the parameters quantifying the anatomical - morphological arrangement of the patellofemoral joint. The biorheometric properties of the knee were evaluated using a custom made measuring apparatus during passive flexion and extension of the knee. RESULTS:Our results confirm that the link between the clinical findings and the X-ray imaging examinations was not evident. On the contrary, the biorheometric examination proved to correlate well with the clinical symptoms of PFPS. Parameters were identified which can characterize the biorheograms of people suffering PFPS. CONCLUSIONS:Analysis of the relationship among the clinical, radiological and biorheometric examinations leads to the recommendation that biorheometric examination is an effective method for the objective assessment of PFPS.

Ice-hockey requires high acceleration and speed sprint abilities, but it is unclear what the distance characteristic is for measuring these capabilities. Therefore, this systematic meta-analysis aims to summarize the sprint reference values for different sprint distances and suggest the appropriate use of ice-hockey straight sprint testing protocols. A total of 60 studies with a pooled sample of 2254 males and 398 females aged 11-37 years were included. However, the pooled data for women was not large enough to permit statistical analysis. The sprint distance used for measuring the reported acceleration and speed was between 4-48 m. Increased test distance was positively associated with increased speed (r = 0.70) and negatively with average acceleration (r = -0.87). Forward skating sprint speed increases with the measured distance up to 26 m and do not differ much from longer distance tests, while acceleration decreases with a drop below 3 m/s at distances 15 m and longer. The highest acceleration (5.89 m/s2 peak, 3.31 m/s2 average) was achieved in the shortest distances up to 7 m which significantly differs from 8-14 m tests. The highest speed (8.1 m/s peak, 6.76 m/s average) has been recorded between 26-39 m; therefore, distances over 39 m are not necessary to achieve maximum speed. Considering match demands and most reported test distances, 6.1 m is the recommended distance for peak acceleration and 30 m for peak speed. The sprint time, acceleration, and speed of each individual and the number of skating strides should be reported in future studies.

Non-contact injury to the anterior cruciate ligament often occurs during jump landings and it is thought that a valgus knee position is particularly risky. We have shown that landings can be categorised according to the loading of the tibiofemoral joint using musculoskeletal modelling and have suggested that a laterally-loaded tibiofemoral joint is analogous to a valgus position. In this study, the landings of 23 men and 27 women were categorised as either laterally (LL) or medially (ML) loaded using a publicly available musculoskeletal model and the time histories of the joint contact and muscle forces were compared. Although the ground reaction force and knee joint kinematics were very similar between the two groups, there were marked differences in the joint contact and muscle forces. The LL group exhibited a greater ankle contact force. The tibiofemoral joint contact force was greater for the LL group early in the landing but greater for the ML group later in the movement. The peak hip contact forces were greater for the ML group and the patellofemoral contact force was greater for the ML group towards the end of the landing. The ML group showed a greater recruitment of the hip musculature early in the movement whereas the LL group relied more on the hamstrings. The ML group showed a greater recruitment of the glutes throughout the movement and of the quadriceps late in the landing. These results support the contention that differences in loading during landing are more associated with landing strategy than gender.

Abstract Femoroacetabular impingement (FAI) in ice hockey is a concern for many athletes. The biomechanics of skating and the injury mechanism, prevalence, identification, and treatment protocols currently available for FAI in ice hockey athletes are important for all coaches and practitioners to understand. This article discusses the underlying anatomical issues and biomechanical considerations surrounding FAI. Furthermore, this article describes the interventions that can be used when encountering FAI and well-established protocols to aid in the return to play. Finally, prevention strategies that can aid in injury prevention are discussed.

Contemporary descriptions of motor control suggest that variability in movement can be indicative of skilled or unskilled performance. Here we used principal component analysis to study the kicking performance of elite and sub-elite soldiers who were highly familiar with the skill in order to compare the variability in the first and second principal components. The subjects kicked a force plate under a range of loaded conditions, and their movement was recorded using optical motion capture. The first principal component explained >92% of the variability across all kinematic variables when analyzed separately for each condition, and both groups and explained more of the variation in the movement of the elite group. There was more variation in the loading coefficient of the first principal component for the sub-elite group. In contrast, for the second principal component, there was more variation in the loading coefficient for the elite group, and the relative magnitude of the variation was greater than for the first principal component for both groups. These results suggest that the first principal component represented the most fundamental movement pattern, and there was less variation in this mode for the elite group. In addition, more of the variability was explained by the hip than the knee angle entered when both variables were entered into the same PCA, which suggests that the movement is driven by the hip.

Impact force and maximum velocity are important indicators of kick efficiency. Therefore, this systematic review compared the front kick (FK) and roundhouse kick (RK), including their impact force, maximum velocity, angular velocity, and execution time, considering various target types and experience levels. Following PRISMA guidelines, the Web of Science, SportDiscus, and PubMed were systematically searched for articles published from January 1982 to May 2022. Normalized kicking values were compared using one-way ANOVA. Eighteen articles included FKs (sample: 113 elite men, 109 sub-elite men, and 46 novices), and twenty-five articles included RKs (sample: 238 elite men, 143 sub-elite men, and 27 novice men). The results indicate that the impact force of the FK were 47% (p < 0.01), 92% (p < 0.01), and 120% (p < 0.01) higher than those of the RK across novice, sub-elite, and elite groups, respectively. Moreover, the maximum foot velocity of the RK was 44% (p < 0.01) and 48% (p < 0.01) higher than that of the FK for the sub-elite and elite groups, respectively. Furthermore, the elite group had 65% (p < 0.01) higher knee extension angular velocity with the RK than with the FK and 138% (p < 0.01) higher hip extension angular velocity with the FK than with the RK. In summary, the findings suggest that the FK is more effective in generating forceful kicks, while the RK has the potential for rapid execution.

Since the flat serve (FS) minimizes the ball spin and kick serve (KS) combined topspin and sidespin, this systematic review aimed to explore the ball impact location (BI) within the FS and KS at the professional men, junior men, and women tennis players. The PRISMA guideline was used, and the original articles were searched in Scopus, Web of Science, and PubMed. The means and standard deviations computed from the distance of BI from the origin within the FS and KS on the x, y, and z axes (global coordinate system) were normalized by the participants’ height and weighted by the number of participants in one-way ANOVA. Ten articles with a pooled sample of 133 males and 51 females aged 11–25 were included. The professional men had more stable BI on the x-axis within the FS by 56% (p < 0.001), within the KS by 58% (p < 0.001), and on the y-axis within the KS by 90% (p < 0.001) than junior men. The professional and junior men had the BI more leftwards from the origin on the x-axis within the KS by 188% (p < 0.001) and 88% (p < 0.001), respectively than within the FS.

PURPOSE: Low load blood flow restriction training (LLBFR) is commonly used as a rehabilitation modality due to its effects on muscle strength and hypertrophy, however little is known about the effect of LLBFR on the mechanics of the movements used during exercise. Methods: Seven strength trained males randomly completed a series of back squats using either LLBFR or high load resistance training (HLRT). Hip, knee and ankle biomechanics were recorded and processed using the FreeBody mathematical model to calculate peak joint contact forces (PJCF) at the hip (HF), medial and lateral tibial-femoral joint (MTFJ, LTFJ) and ankle (AF). Muscle activity was recorded via EMG at the prime movers of the lower-limb. Results: LLBFR demonstrated significantly smaller hip abduction and knee external rotation than HLRT. Both modalities demonstrated a significant increase in hip, knee and ankle sagittal plane motion with protocol duration. PJCF at the HF and AF demonstrated significantly higher forces in HLRT in comparison to LLBFR whilst MTFJ and LTFJ experienced non-significant differences between groups with time effects demonstrated with some EMG measures. Conclusion: This investigation offers an insight into hip, knee and ankle kinematics and joint kinetics during LLBFR and HLRT

INTRODUCTION The efficiency of front kick is related to the kicking technique. Thus, the aim of this study was to find the kinematic determinants of front kick dynamics across different performance and loading levels (no load to 45-kg load). MATERIALS AND METHODS Twenty-four elite and sub-elite professional military personnel (26.8 ± 10.1 years, 84.2 ± 5.4 kg, 181.1 ± 6.4 cm) performed six front kicks into a force plate across five different loading conditions. Three-dimensional kinematics of the kicks was quantified and included velocity of the hip (Vhip), velocity of the knee (Vknee), velocity of the shoulder (Vshoulder), velocity of the foot (Vfoot), angular velocity of the knee (AVknee), and angular velocity of the hip (AVhip). RESULTS The main kinematic differences between the two groups were that the sub-elite group had an increased kick time for all loading conditions (P < .001) and a lower Vfoot (P = .05) and a decreased Vhip and Vshoulder (P < .05) in the highest load condition. Vhip and AVhip were the best predictors (up to R2 = 0.58; P = .020) of peak force and impact force during no-load or loaded kicking at the elite level. Typical predictors of impulse in the elite group were AVhip, Vhip, and Vshoulder and those in the sub-elite group were AVknee and Vfoot. CONCLUSIONS The kinematic variables provide good predictions of kicking dynamics; however, the best predictor varies with the loading conditions and performance levels. Hip motion is the main differentiating factor.

Astronauts who spend prolonged time in microgravity on the International Space Station can experience a significant reduction in physical fitness. Jumping exercises represent a potential solution to this problem as the European Space Agency has demonstrated that the deconditioning effect of long-term bed-rest can be countered with around four minutes per day of jumping. The purpose of this study was to evaluate if repeated jumping is possible in microgravity and if the transmission of impact forces and vibration to the aircraft can be minimised. Five subjects performed repeated jumping on a custom jump sled both in microgravity during a parabolic flight campaign and in normal gravitational conditions. Forces expressed by the user and transmitted to the aircraft were quantified using a bespoke instrumentation system. These results show, for the first time, that repeated horizontal jumping is possible in microgravity, and that force transmission can be minimised by using a custom supine jump sled. The peak effective ground reaction force experienced by the user was sensitive to both the style of jumping used and resistance employed. These results open the door to the next generation of exercise countermeasures for deep space exploration. In particular, we have qualified the High Frequency Impulse for Microgravity (HIFIm) exercise device to a Technology Readiness Level of 6 making it a leading candidate to replace the Advanced Resistive Exercise Device (ARED) which has been in service since 2009.

Review question / Objective: To summarize the sprint reference acceleration and speed values for different sprint distances and suggest optimal unification of ice-hockey straight sprint testing. Eligibility criteria: The title and abstract screening was done by two researchers (PS and RR) who selected a set of articles for full text screening, where the inclusion criteria were: 1) male or female ice-hockey players; 2) any cross-sectional or intervention study; 3) tests of ice-hockey sprinting over any distance or any battery of conditioning tests that included straight-line sprints; and, 4) results reported straight-line sprint distance, speed, time, or acceleration. In the case of disagreement between the evaluating authors, the final decision was made by a third author (MV).The full text screening exclusion criteria were: 1) if the article was not in English; 2) the testing did not include straight-line sprinting; 3) the reported values did not include data distribution; 4) the study reported only maximum speed without skating time or average speed; 5) the end of the sprint was defined by the point the player stopped sprinting; 6) the measurement was made with a stopwatch; and, 7) the study had high bias estimation. The maximum speed test was not included due to the uncertain velocity conditions at beginning of testing distance. The bias estimation was performed using the JBI (Joanna Briggs Institute) Critical Appraisal Checklist for Analytical Cross Sectional Studies (supplementary material 1).