A Systematic Review and Meta-Analysis of Wearable Satellite System Technology for Linear Sprint Profiling: Technological Innovations and Practical Applications.

ABSTRACT: Cormier, P, Meylan, C, Agar-Newman, D, Geneau, D, Epp-Stobbe, A, Lenetsky, S, and Klimstra, M. A systematic review and meta-analysis of wearable satellite system technology for linear sprint profiling: technological innovations and practical applications. J Strength Cond Res 38(2): 405-418, 2024-An emerging and promising practice is the use of global navigation satellite system (GNSS) technology to profile team-sports athletes in training and competition. Therefore, the purpose of this narrative systematic review with meta-analysis was to evaluate the literature regarding satellite system sensor usage for sprint modeling and to consolidate the findings to evaluate its validity and reliability. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, an electronic search of the databases, PubMed and SPORTDiscus (EBSCO), was conducted. Concurrent validity and reliability studies were considered, and 16 studies were retained for the review from the initial 1,485 studies identified. The effects on outcomes were expressed as standardized mean differences (SMDs, Cohen's d ) for each outcome (i.e., maximal sprint speed [MSS], the acceleration constant [τ], maximal theoretical velocity [ V0 ], relative force [ F0 ], and relative power [P max ]). Effect magnitudes represented the SMD between GNSS-derived and criterion-derived (i.e., radar and laser) and resulted in the following estimates: small for MSS ( d = 0.22, 95% CI 0.01 to 0.42), τ ( d = -0.18, 95% CI -0.60 to 0.23), V0 ( d = 0.14, 95% CI -0.08 to 0.36), relative F0 ( d = 0.15, 95% CI -0.25 to 0.55), and relative P max ( d = 0.21, 95% CI -0.16 to 0.58). No publication bias was identified in meta-analyzed studies and moderator analysis revealed that several factors (sampling rate and sensor manufacturer) influenced the results. Heterogeneity between studies was considered moderate to high. This highlighted the differences between studies in sensor technology differences (i.e., sampling rate, sensor fusion, and satellite network acquisition), processing techniques, criterion technology used, sprint protocols, outcome reporting, and athlete characteristics. These findings may be useful in guiding improvements in sprint modeling using GNSS technology and enable more direct comparisons in future research. Implementation of all-out linear sprint efforts with GNSS technology can be integrated into sport-specific sessions for sprint modeling when robust and consistent data processing protocols are performed, which has important implications for fatigue monitoring, program design, systematic testing, and rehabilitation in individual and team sports.

The Relationship Between Lower-Body Force-Time Variables and Skating Performance in Female Ice Hockey Players.

PURPOSE: Ice hockey is a team invasion sport characterized by repeated high-intensity skating efforts, technical and tactical skill, physical contact, and collisions requiring considerable levels of muscular strength. The purpose of this study was to evaluate the relationships between lower-body vertical force-time metrics and skating qualities in subelite female ice hockey players. METHODS: A cross-sectional cohort design was employed utilizing 14 athletes (body mass = 66.7 [1.8] kg; height = 171.6 [6.2] cm; age = 21.1 [1.7] y). The relationships between metrics of lower-body strength collected from a drop jump, squat jump, countermovement jump, loaded countermovement jump, and an isometric squat and 4 skating qualities collected from a linear sprint, repeated sprint test, and a multistage aerobic test were evaluated. RESULTS: The regression models revealed a positive relationship between relative peak force in the isometric squat and skating multistage aerobic test performance (r2 = .388; P = .017) and a positive relationship between repeated-sprint ability and eccentric mean force during the loaded countermovement jump (r2 = .595; P = .001). No significant relationships were observed between strength metrics and skating acceleration or maximal velocity. CONCLUSIONS: These data suggest that skating ability is most affected by relative isometric strength in female ice hockey players. It is recommended that practitioners focus training on tasks that improve relative force output. It is also recommended that isometric relative peak force be used as a monitoring metric for this cohort.

Concurrent Validity and Reliability of Different Technologies for Sprint-Derived Horizontal Force-Velocity-Power Profiling.

ABSTRACT: Cormier, P, Tsai, M-C, Meylan, C, Agar-Newman, D, Epp-Stobbe, A, Kalthoff, Z, and Klimstra, M. Concurrent validity and reliability of different technologies for sprint-derived horizontal force-velocity-power profiling. J Strength Cond Res 37(6): 1298-1305, 2023-This study evaluated the validity and reliability of common systems to assess sprint-derived horizontal force-velocity-power ( FVPH ) profile metrics. Two double constellation athlete monitoring systems (STATSports Apex, Catapult Vector S7) and one timing gate system were compared with a radar gun for the computation of FVPH metrics. Intersystem validity was assessed using intraclass correlation coefficients (ICC), Pearson's correlation coefficients ( R2 ), and Bland-Altman plots with absolute and percent agreement. Intrasystem reliability was assessed with agreement bias and ICC. STATSports demonstrated moderate agreement for F0 , Pmax , τ, and Drf (8.62, 6.46, -9.81, and 9.96%, respectively) and good agreement for V0 and MSS (-2.18 and -1.62%). Catapult displayed good agreement across all metrics ( F0 , V0 , Pmax , MSS, τ, and Drf : -0.96, -0.89, -1.85, -0.84, 0.38, and -0.27%, respectively). Timing gates demonstrated good agreement with V0 and MSS (-2.62 and -1.71%) and poor agreement with F0 , Pmax , τ, and Drf (19.17, 16.64, -20.49, and 20.18%, respectively). Intrasystem reliability demonstrated good agreement (<2% bias) with very large to near-perfect ICC (0.84-0.99) for Catapult and STATSports systems. Overall, GPS/GNSS 10 Hz technology is reliable across devices and can provide moderate-to-good accuracy of FVPH metrics in single maximal effort sprints. However, Catapult provided better agreement for more FVPH metrics than STATSports, which may be related to differences in proprietary algorithms. Also, modeling timing gate data using current FVPH profiling techniques results in poor bias that requires greater investigation. GPS/GNSS data can be used for FVPH profiling, which could inform performance and rehabilitation processes.

Within Session Exercise Sequencing During Programming for Complex Training: Historical Perspectives, Terminology, and Training Considerations.

The primary aim of this narrative review was to outline the historical genesis of resistance training strategies that incorporate high-load, low-velocity exercises and low-load, high-velocity exercises in the same training session allowing for different "exercise sequences" to be simultaneously implemented. Discrepancies between scientific works and the terminology used within contemporary sport science publications are identified. Upon review of the literature, we propose "complex training" to be considered an umbrella term with 4 different implementations, generally used to indicate a method in which movement velocity or load is altered between sets and/or exercises within the same session with the aim of improving slow and fast force expression. We propose the following terminology for said implementations: contrast training-exercise sequence with alternating high-load and low-load (higher-velocity) exercises in a set-by-set fashion within the same session (corresponding with 'contrast pairs' and 'intra-contrast rest'); descending training-several sets of high-load (e.g., back squat) exercises completed before the execution of several sets of low-load, higher-velocity (e.g., vertical jump) exercises within the same session; ascending training-several sets of low-load, higher-velocity exercises completed before several sets of high-load exercises within the same session; and French contrast training-subset of contrast training in which a series of exercises are performed in sequence within a single session: heavy compound exercise, plyometric exercise, light-to-moderate load compound exercise that maximises movement speed (i.e., external power), and a plyometric exercise (often assisted). Finally, practical applications and training considerations are presented.

The validity of the Push Band 2.0 to determine speed and power during progressively loaded squat jumps.

ABSTARCTThe PUSH band 2.0 is a wearable technology used to measure mean and peak velocity and power in strength-based movements. The agreement between the PUSH band 2.0 and the criterion measure (force plates) during progressively loaded squat jumps was assessed. Fifteen participants performed 3 squat jumps at increasing loads. Linear regression and Bland-Altman plots assessed data simultaneously recorded from both devices. Mean velocity and power showed deviation from the identity line and an overestimation of 7.40% and 25%, respectively. Peak velocity and power showed an overestimation of 14% and underestimation of 6%, respectively. The results support the use of Push Band 2.0 to measure velocity during ballistic squat movements. However, errors in power measurement are greater than acceptable to support in-field use. While peak velocity maintains a consistent overestimation bias across various velocities, mean velocity error increases at higher velocities and can only be considered valid at slow velocities.

Anthropometric and Physical Qualities of International Level Female Rugby Sevens Athletes Based on Playing Position.

Agar-Newman, DJ, Goodale, TL, and Klimstra, MD. Anthropometric and Physical Qualities of International Level Female Rugby Sevens Athletes Based on Playing Position. J Strength Cond Res 31(5): 1346-1352, 2017-The purpose of this study was to profile international level female sevens athletes and determine whether anthropometric and physical qualities are able to differentiate between backs and forwards. Twenty-four subjects with a mean (±SD) age of 22.8 ± 4.0 years and body weight of 69.4 ± 5.2 kg were sampled from a national team training program, ranked in the top 3 on the IRB Women's Sevens World Series. Anthropometric (height, body mass, and sum of 7 skinfolds) and performance measures (power clean, front squat, bench press, neutral grip pull-up, 40-m sprint, and 1,600-m run) were collected across the 2013-2014 centralized period and compared across playing position. The 13 backs (mean age ± SD = 21.3 ± 3.5 years) and 11 forwards (mean age ± SD = 24.5 ± 4.0 years) had significant differences in body mass (66.40 ± 3.48 vs. 72.87 ± 4.79 kg) and initial sprint momentum (366.8 ± 19.8 vs. 399.2 ± 22.4 kg·m·s). However no other measures showed positional differences. The lack of positional differences in female rugby sevens may be due to the multifarious physical requirements of a sevens athlete, leading to a generic athletic profile, or perhaps due to a lack of selective pressure. Also, it is conceivable that the anthropometric and physical qualities measured in this study lacked the necessary precision or failed to capture the unique attributes of each position. In conclusion, this is the first investigation profiling international level female sevens athletes. The normative data presented within this article highlight the physical requirements of female sevens athletes for strength and conditioning practitioners. In addition, the lack of positional differences discovered should impact the training program design.

Efficacy of horizontal jumping tasks as a method for talent identification of female rugby players.

The purpose of this study was to explore the relationship between horizontal jumping tasks (standing long jump [SLJ] and standing triple jump [STJ]) and sprint speed (initial sprint speed [ISS] and maximum sprint speed [MSS]) in elite female rugby athletes. Data were collected from provincial, under 20 international fifteens players, in addition to senior sevens international level female rugby athletes (n = 114). Body weight, SLJ, STJ, 10-m sprint speed (ISS), 30- to 40-m sprint speed (MSS), initial sprint momentum, and maximal sprint momentum were analyzed. When categorized by horizontal jumping ability, there was a significant difference in sprint speeds (p < 0.001) between the top 50% and bottom 50% groups. Examining the relationship between horizontal jumping tasks and sprinting speed revealed a stronger correlation in the slowest 50% of athletes compared with the fastest 50%. A linear regression developed from STJ and body weight adequately predicted ISS (r = 0.645, p < 0.001) and MSS (r = 0.761, p < 0.001). In conclusion, horizontal jumping tasks can be used as a valuable performance test to identify differences of sprinting ability in elite female rugby players. However, the relationship between horizontal jumping tasks and sprinting speed seems to decrease in faster athletes. Further, STJ and body weight can be used to predict both ISS and MSS. Based on these data, it is suggested that only STJ be collected when identifying potential sprinting talent in female rugby athletes and caution be used when generalizing results across varying levels of athletes.

Transfer effect of strength and power training to the sprinting kinematics of international rugby players.

Increasing lower-body strength is often considered to be important for improving the sprinting speed of rugby players. This concept was examined in a group (n = 40) of international rugby players in a 2-part study. The players were tested for body mass (BM), 1 repetition maximum power clean (PC), and front squat, as well as triple broad jump and broad jump. In addition, speed over 40 m was tested, with timing gates recording the 0- to 10-m and 30- to 40-m sections to assess acceleration and maximal velocity. Two video cameras recorded the 2 splits for later analysis of sprinting kinematics. The players were divided into a fast group (n = 20) and a slow group (n = 20) for both acceleration and maximal velocity. In the second part of the study, a group (n = 15) of players were tracked over a 1-year period to determine how changes in strength corresponded with changes in sprinting kinematics. The fast groups for both acceleration and maximal velocity showed greater levels of strength (d = 0.5-1.8), lower ground contact times (d = 0.8-2.1), and longer stride lengths (d = 0.5-1.3). There was a moderate improvement over 1 year in PC/BM (0.08 kg·kg, p = 0.008, d = 0.6), and this had a strong relationship with the change in maximal velocity stride length (r = 0.70). Acceleration stride length also had a large improvement over 1 year (0.09 m, p = 0.003, d = 0.81). Although increasing lower-body strength is likely important for increasing sprinting speed of players with low training backgrounds, it may not have the same effect with highly trained players.