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PURPOSE: Post-exercise passive heating has been reported to augment adaptations associated with endurance training. The current study evaluated the effect of a 4-week remotely administered, post-exercise passive leg heating protocol, using an electrically heated layering ensemble, on determinants of endurance performance. METHODS: Thirty recreationally trained participants were randomly allocated to either a post-exercise passive leg heating (PAH, n = 16) or unsupervised training only control group (CON, n = 14). The PAH group wore the passive heating ensemble for 90-120 min/day, completing a total of 20 (16 post-exercise and 4 stand-alone leg heating) sessions across 4 weeks. Whole-body (peak oxygen uptake, gas exchange threshold, gross efficiency and pulmonary oxygen uptake kinetics), single-leg exercise (critical torque and NIRS-derived muscle oxygenation), resting vascular characteristics (flow-mediated dilation) and angiogenic blood measures (nitrate, vascular endothelial growth factor and hypoxia inducible factor 1-α) were recorded to characterize the endurance phenotype. All measures were assessed before (PRE), at 2 weeks (MID) and after (POST) the intervention. RESULTS: There was no effect of the intervention on test of whole-body endurance capacity, vascular function or blood markers (p > 0.05). However, oxygen kinetics were adversely affected by PAH, denoted by a slowing of the phase II time constant; τ (p = 0.02). Furthermore, critical torque-deoxygenation ratio was improved in CON relative to PAH (p = 0.03). CONCLUSION: We have demonstrated that PAH had no ergogenic benefit but instead elicited some unfavourable effects on sub-maximal exercise characteristics in recreationally trained individuals.
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Despite the growing popularity of women's rugby, there is a lack of research understanding the contribution of place-kicking to match outcomes. This study aims to establish the characteristics and contribution of place-kicking to women's international Rugby Union and evaluate the performance of place-kickers while accounting for factors that contribute to kick difficulty. Data from 674 place-kicks across 80 matches were analysed. A binomial generalised linear mixed model (GLMM) was used to predict the probability of kick success. 60.5% of place-kicks were successful, and they contributed 23.9% of all points scored; conversions accounted for 16.8% and penalties 7.1%. Kick success percentages for conversions (56.9%) and penalties (78.3%) significantly differed (p < 0.01). Kick distance and angle were significant (p < 0.01) predictors of kick success and the GLMM had a prediction accuracy of 73.6%. The performance rankings of kickers changed when comparing observed and expected success, highlighting the need to consider contextual factors contributing to kick difficulty when evaluating performance. The GLMM results provide valuable insights for coaches and players to make informed decisions, for example, whether to attempt a place-kick when a penalty is awarded, by enabling predictions of place-kick success. This could enhance a team's chances of winning matches.
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Lower-limb wearable resistance (WR) facilitates targeted resistance-based training during sports-specific movement tasks. The purpose of this study was to determine the effect of two different WR placements (thigh and shank) on joint kinematics during the acceleration phase of sprint running. Eighteen participants completed maximal effort sprints while unloaded and with 2% body mass thigh- or shank-placed WR. The main findings were as follows: 1) the increase to 10 m sprint time was small with thigh WR (effect size [ES] = 0.24), and with shank WR, the increase was also small but significant (ES = 0.33); 2) significant differences in peak joint angles between the unloaded and WR conditions were small (ES = 0.23-0.38), limited to the hip and knee joints, and <2° on average; 3) aside from peak hip flexion angles, no clear trends were observed in individual difference scores; and, 4) thigh and shank WR produced similar reductions in average hip flexion and extension angular velocities. The significant overload to hip flexion and extension velocity with both thigh- and shank-placed WR may be beneficial to target the flexion and extension actions associated with fast sprint running.
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Entrenamiento de Fuerza , Carrera , Dispositivos Electrónicos Vestibles , Humanos , Extremidad Inferior , Aceleración , Fenómenos BiomecánicosRESUMEN
The aim of this study was to understand how a place kicker's range is limited by their approach to the ball and their physical characteristics. Thirty-three kickers performed maximal place kicks and vertical jumps in a laboratory. Whole-body motion and ground reaction forces during the approach phase of the kicks, jump performance and anthropometric measurements of those whose predicted maximum distance was limited by range (n = 17) rather than accuracy were analysed. Principal component analysis (PCA) reduced the number of variables considered before stepwise regression analyses assessed variance in place kick maximum distance and associated criteria. Four components, explaining 94% of the variance in maximum distance, were extracted from the PCA: width of approach, anterior-posterior body position, centre-of-mass height and lower limb strength. Lower limb strength was a significant predictor of both kicking foot velocity (R2 = 0.55, p = 0.001) and ball velocity magnitude (R2 = 0.57, p < 0.001). However, maximum distance was determined by body position during the approach (antero-posterior position, R2 = 0.52, p = 0.001 and centre-of-mass height, R2 = 0.12, p = 0.049). This highlights the importance of considering three-dimensional motion of the kicker alongside their physical capabilities to understand place kicking range.
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Rugby , Fútbol , Fenómenos Biomecánicos , Pie , Humanos , Extremidad Inferior , Movimiento (Física)RESUMEN
In track sprinting, acceleration performance is largely determined by the ability to generate a high ratio of forces (RF), but the technical features associated with this remain unknown. This study therefore investigated the relationships between selected kinematic characteristics and RF during the initial acceleration phase. Fourteen male sprinters completed two maximal 60 m sprints from a block start. Full-body kinematic and external kinetic data were obtained from the first four steps, and the relationships between selected kinematic characteristics and mean RF over the first four steps were determined. Placing the stance foot further behind (or less far in front of) the whole-body centre of mass at touchdown was significantly related to greater RF (r = -0.672), and more anterior orientation of the proximal end of the foot (r = -0.724) and shank (r = -0.764) segments at touchdown were also significantly related to greater RF. Following touchdown, greater ankle dorsiflexion range of motion during early stance was significantly related to greater RF (r = 0.728). When aiming to enhance RF during initial acceleration, practitioners should be encouraged to focus on lower leg configurations when manipulating touchdown distance, and the role of dorsiflexion during early stance is also an important consideration.
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Rendimiento Atlético , Carrera , Humanos , Masculino , Fenómenos Biomecánicos , Extremidad Inferior , AceleraciónRESUMEN
Sprint acceleration is an important motor skill in team sports, thus consideration of techniques adopted during the initial steps of acceleration is of interest. Different technique strategies can be adopted due to multiple interacting components, but the reasons for, and performance implications of, these differences are unclear. 29 professional rugby union backs completed three maximal 30 m sprints, from which spatiotemporal variables and linear and angular kinematics during the first four steps were obtained. Leg strength qualities were also obtained from a series of strength tests for 25 participants, and 13 participants completed the sprint protocol on four separate occasions to assess the reliability of the observed technique strategies. Using hierarchical agglomerative cluster analysis, four clear participant groups were identified according to their normalised spatiotemporal variables. Whilst significant differences in several lower limb sprint kinematic and strength qualities existed between groups, there were no significant between-group differences in acceleration performance, suggesting inter-athlete technique degeneracy in the context of performance. As the intra-individual whole-body kinematic strategies were stable (mean CV = 1.9% to 6.7%), the novel approach developed and applied in this study provides an effective solution for monitoring changes in acceleration technique strategies in response to technical or physical interventions.
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Rendimiento Atlético , Fútbol Americano , Carrera , Aceleración , Fenómenos Biomecánicos , Humanos , Reproducibilidad de los ResultadosRESUMEN
This study determined the effects of two wearable resistance (WR) placements (i.e. thigh and shank) on horizontal force-velocity and impulse measures during sprint running acceleration. Eleven male athletes performed 50 m sprints either unloaded or with WR of 2% body mass attached to the thigh or shank. In-ground force platforms were used to measure ground reaction forces and determine dependent variables of interest. The main findings were: 1) increases in sprint times and reductions in maximum velocity were trivial to small when using thigh WR (0.00-1.93%) and small to moderate with shank WR (1.56-3.33%); 2) athletes maintained or significantly increased horizontal force-velocity mechanical variables with WR (effect size = 0.32-1.23), except for theoretical maximal velocity with thigh WR, and peak power, theoretical maximal velocity and maximal ratio of force with shank WR; 3) greater increases to braking and vertical impulses were observed with shank WR (2.72-26.3% compared to unloaded) than with thigh WR (2.17-12.1% compared to unloaded) when considering the entire acceleration phase; and, 4) no clear trends were observed in many of the individual responses. These findings highlight the velocity-specific nature of this resistance training method and provide insight into what mechanical components are overloaded by lower-limb WR.
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Rendimiento Atlético/fisiología , Extremidad Inferior/fisiología , Entrenamiento de Fuerza/métodos , Carrera/fisiología , Dispositivos Electrónicos Vestibles , Aceleración , Adolescente , Adulto , Fenómenos Biomecánicos , Humanos , Masculino , Entrenamiento de Fuerza/instrumentación , Soporte de Peso/fisiología , Adulto JovenRESUMEN
PURPOSE: While kicking in Rugby Union can be influential to match outcome, the epidemiology of kicking injuries remains unknown. This study therefore aimed to investigate the epidemiology of injuries attributed to kicking in professional rugby, including playing position-specific effects and differences in kicking volumes and kick types. METHODS: Fifteen seasons of injury surveillance data and two seasons of match kicking characteristics from professional rugby players were analyzed. Incidence, propensity, and severity of kicking-related injuries were calculated together with the locations and types of these injuries. Position-related differences in match kicking types and volumes were also established. RESULTS: Seventy-seven match and 55 training acute-onset kicking injuries were identified. The match kicking injury incidence for backs was 1.4/1000 player-match-hours. Across all playing positions, the propensity for match kicking injury was 0.57 injuries/1000 kicks. Fly-halves sustained the greatest proportion of match kicking injuries (47%) and performed the greatest proportion of match kicks (46%); an average propensity for match kicking injury (0.58/1000 kicks). Scrum-halves executed 27% of match-related kicks but had a very low propensity for match kicking injury (0.17/1000 kicks). All other positional groups executed a small proportion of match-related kicks but a high propensity for match kicking injury. Ninety-two percent of match kicking injuries occurred in the pelvis or lower limb, with the majority sustained by the kicking limb. 21% of all match kicking injuries were associated with the rectus femoris muscle. CONCLUSION: Match kicking profiles and kicking injuries sustained are position-dependent, which provides valuable insight for developing player-specific conditioning and rehabilitation protocols.
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Traumatismos en Atletas/epidemiología , Fútbol Americano/lesiones , Extremidad Inferior/lesiones , Inglaterra/epidemiología , Humanos , Masculino , Estudios ProspectivosRESUMEN
Successful sprinting depends on covering a specific distance in the shortest time possible. Although external forces are key to sprinting, less consideration is given to the duration of force application, which influences the impulse generated. This study explored relationships between sprint performance measures and external kinetic and kinematic performance indicators. Data were collected from the initial acceleration, transition and maximal velocity phases of a sprint. Relationships were analysed between sprint performance measures and kinetic and kinematic variables. A commonality regression analysis was used to explore how independent variables contributed to multiple-regression models for the sprint phases. Propulsive forces play a key role in sprint performance during the initial acceleration (r = 0.95 ± 0.03) and transition phases (r = 0.74 ± 0.19), while braking duration plays an important role during the transition phase (r = -0.72 ± 0.20). Contact time, vertical force and peak propulsive forces represented key determinants (r = -0.64 ± 0.31, r = 0.57 ± 0.35 and r = 0.66 ± 0.30, respectively) of maximal velocity phase performance, with peak propulsive force providing the largest unique contribution to the regression model for step velocity. These results clarified the role of force and time variables on sprinting performance.
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Rendimiento Atlético/fisiología , Carrera/fisiología , Aceleración , Fenómenos Biomecánicos , Femenino , Humanos , Cinética , Masculino , Análisis de Regresión , Estudios de Tiempo y MovimientoRESUMEN
In table tennis the follow-through action after a shot is an important part of skill execution. In this experiment, we aimed to extend literature around the contextual interference effect by investigating whether the way the follow-through is organised in practice affects learning of the backhand shot in table tennis. Thirty unskilled participants were allocated to blocked-variable practice, random-variable practice or a control-constant group and aimed backhand shots towards a target following ball projection from a machine. Each group completed these shots in a pre-test, a training phase with follow-through manipulations, a post-test, and a retention test. The random-variable group improved their shot accuracy from pre-test to post-test and from pre-test to retention test (both P < 0.01, d = 1.03), whereas neither the blocked-variable nor the control-constant group displayed any change in shot accuracy. Practising the follow-through in a random-variable fashion enhanced learning of the preceding shot compared with blocked-variable practice or no follow-through instructions. The benefits of learning motor skills under conditions of high contextual interference also apply to how follow-through actions are organised. The findings are valuable to coaches and suggest that instructions related to the follow-through action should be considered as well as the primary skill itself.
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Rendimiento Atlético , Aprendizaje , Destreza Motora , Práctica Psicológica , Tenis/fisiología , Adulto , Femenino , Humanos , Masculino , Adulto JovenRESUMEN
We examined the effects of anxiety and situation-specific contextual information on attentional, interpretational, and behavioural processes underpinning perceptual-motor performance as proposed by Nieuwenhuys and Oudejans (Psychological Research 76:747-759; Nieuwenhuys, Oudejans, Psychological Research 76:747-759, 2012) using an in situ task. Twelve skilled cricket batsmen played against a skilled spin bowler under conditions manipulated to induce low and high levels of anxiety and the presence of low and high levels of situation-specific context. High anxiety decreased the number of good bat-ball contacts, while high levels of situation-specific context increased the number of times the ball was missed. When under high anxiety, participants employed significantly more fixations of shorter duration to more locations, but the effects of anxiety were restricted to the attentional level only. Situation-specific context affected performance and behavioural measures but not anxiety, cognitive load or perceptual-cognitive processes, suggesting that performance is influenced through different mechanisms from anxiety that are independent of working memory load.
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Ansiedad , Atención , Desempeño Psicomotor , Rendimiento Atlético , Humanos , Masculino , Memoria a Corto Plazo , Adulto JovenRESUMEN
A more horizontally oriented ground reaction force vector is related to higher levels of sprint acceleration performance across a range of athletes. However, the effects of acute experimental alterations to the force vector orientation within athletes are unknown. Fifteen male team sports athletes completed maximal effort 10-m accelerations in three conditions following different verbal instructions intended to manipulate the force vector orientation. Ground reaction forces (GRFs) were collected from the step nearest 5-m and stance leg kinematics at touchdown were also analysed to understand specific kinematic features of touchdown technique which may influence the consequent force vector orientation. Magnitude-based inferences were used to compare findings between conditions. There was a likely more horizontally oriented ground reaction force vector and a likely lower peak vertical force in the control condition compared with the experimental conditions. 10-m sprint time was very likely quickest in the control condition which confirmed the importance of force vector orientation for acceleration performance on a within-athlete basis. The stance leg kinematics revealed that a more horizontally oriented force vector during stance was preceded at touchdown by a likely more dorsiflexed ankle, a likely more flexed knee, and a possibly or likely greater hip extension velocity.
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Aceleración , Rendimiento Atlético/fisiología , Extremidad Inferior/fisiología , Carrera/fisiología , Fenómenos Biomecánicos , Marcha/fisiología , Humanos , Masculino , Músculo Esquelético/fisiología , Postura/fisiología , Análisis y Desempeño de Tareas , Adulto JovenRESUMEN
PURPOSE: This study implemented 18-week individual-specific sprint acceleration training interventions in elite male rugby backs based on their predetermined individual technical needs and evaluated the effectiveness of these interventions. METHODS: Individual-specific interventions were prescribed to 5 elite rugby backs over an 18-week period. Interventions were informed by the relationships between individual technique strategies and initial acceleration performance, and their strength-based capabilities. Individual-specific changes in technique and initial acceleration performance were measured at multiple time points across the intervention period and compared with 3 control participants who underwent their normal training. RESULTS: Of the technique variables intentionally targeted during the intervention period, moderate to very large (|d| = 0.93-3.99) meaningful changes were observed in the participants who received an individual-specific intervention but not in control participants. Resultant changes to the intervention participants' whole-body kinematic strategies were broadly consistent with the intended changes. Moderate to very large (|d| = 1.11-2.82) improvements in initial acceleration performance were observed in participants receiving individual-specific technical interventions but not in the control participants or the participant who received an individual-specific strength intervention. CONCLUSIONS: Individual-specific technical interventions were more effective in manipulating aspects of acceleration technique and performance compared with the traditional "one-size-fits-all" approach adopted by the control participants. This study provides a novel, evidence-based approach for applied practitioners working to individualize sprint-based practices to enhance acceleration performance.
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Rendimiento Atlético , Fútbol Americano , Carrera , Humanos , Masculino , Rugby , AceleraciónRESUMEN
PURPOSE: This study sought to quantify the within-individual relationships between spatiotemporal variables and initial acceleration sprint performance in elite rugby backs and to establish a normative data set of relevant strength-based measures. METHODS: First, the spatiotemporal variables, ratios of step length to step rate and of contact time to flight time, and initial acceleration performance were obtained from 35 elite male rugby backs (mean [SD] age 25 [3] y) over the first 4 steps of 3 sprints. Angular and linear kinematic aspects of technique and strength-based qualities were collected from 25 of these participants. Second, the same spatiotemporal variables were collected from 19 of the participants on 3 further occasions (12 trials in total) to determine the within-individual associations of these variables and initial acceleration performance. RESULTS: Moderate to very large meaningful within-individual relationships (|r| = .43-.88) were found between spatiotemporal variables and initial acceleration performance in 17 of the 19 participants. From these relationships, a theoretically "desirable" change in whole-body kinematic strategy was individually determined for each participant, and normative strength-based measures to contextualize these were established. CONCLUSIONS: Meaningful within-individual relationships are evident between sprint spatiotemporal variables and initial acceleration performance in elite rugby backs. Individualized approaches are therefore necessary to understand how aspects of technique relate to initial acceleration performance. This study provides an objective, evidence-based approach for applied practitioners to identify the initial acceleration technical needs of individual rugby backs.
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Rendimiento Atlético , Fútbol Americano , Humanos , Masculino , Adulto , Rugby , Aceleración , Fenómenos BiomecánicosRESUMEN
PURPOSE: The efficacy of isolated and relative performance indicators (PIs) has been compared in rugby union; the latter more effective at discerning match outcomes. However, this methodology has not been applied in women's rugby. The aim of this study was to identify PIs that maximize prediction accuracy of match outcome, from isolated and relative data sets, in women's rugby union. METHODS: Twenty-six PIs were selected from 110 women's international rugby matches between 2017 and 2022 to form an isolated data set, with relative data sets determined by subtracting corresponding opposition PIs. Random forest classification was completed on both data sets, and feature selection and importance were used to simplify models and interpret key PIs. Models were used in prediction on the 2021 World Cup to evaluate performance on unseen data. RESULTS: The isolated full model correctly classified 75% of outcomes (CI, 65%-82%), whereas the relative full model correctly classified 78% (CI, 69%-86%). Reduced respective models correctly classified 74% (CI, 65%-82%) and 76% (CI, 67%-84%). Reduced models correctly predicted 100% and 96% of outcomes for isolated and relative test data sets, respectively. No significant difference in accuracy was found between data sets. In the relative reduced model, meters made, clean breaks, missed tackles, lineouts lost, carries, and kicks from hand were significant. CONCLUSIONS: Increased relative meters made, clean breaks, carries, and kicks from hand and decreased relative missed tackles and lineouts lost were associated with success. This information can be utilized to inform physical and tactical preparation and direct physiological studies in women's rugby.
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Rugby , Extremidad Superior , Humanos , Femenino , Bosques AleatoriosRESUMEN
Two-dimensional analyses of sprint kinetics are commonly undertaken but often ignore the metatarsalphalangeal (MTP) joint and model the foot as a single segment. Due to the linked-segment nature of inverse dynamics analyses, the aim of this study was to investigate the effect of ignoring the MTP joint on the calculated joint kinetics at the other stance leg joints during sprinting. High-speed video and force platform data were collected from four to five trials for each of three international athletes. Resultant joint moments, powers, and net work at the stance leg joints during the first stance phase after block clearance were calculated using three different foot models. By ignoring the MTP joint, peak extensor moments at the ankle, knee, and hip were on average 35% higher (p < .05 for each athlete), 40% lower (p < .05), and 9% higher (p > .05), respectively, than those calculated with the MTP joint included. Peak ankle and knee joint powers and net work at all joints were also significantly (p < .05) different. By ignoring a genuine MTP joint plantar flexor moment, artificially high peak ankle joint moments are calculated, and these also affect the calculated joint kinetics at the knee.
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Pierna/fisiología , Articulación Metatarsofalángica/fisiología , Modelos Biológicos , Contracción Muscular/fisiología , Músculo Esquelético/fisiología , Rango del Movimiento Articular/fisiología , Carrera/fisiología , Adulto , Simulación por Computador , Femenino , Humanos , Cinética , Masculino , Adulto JovenRESUMEN
In complex movements, centre of mass translation is achieved through effective joint and segment rotations. Understanding segment organisation and coordination is therefore paramount to understanding technique. This study sought to comprehensively describe inter- and intra-limb coordination and assess step-to-step changes and between-individual variation in coordination during initial sprint acceleration. Twenty-one highly trained to world class male (100â m PB 9.89-11.15â s) and female (100â m PB:11.46-12.14â s) sprinters completed sprint trials of at least 20â m from which sagittal plane kinematics were obtained for the first four steps using inertial measurement units (200â Hz). Thigh-thigh, trunk-shank and shank-foot coordination was assessed using a modified vector coding and segment dominancy approach. Common coordination patterns emerged for all segment couplings across sexes and performance levels, suggesting strong task constraints. Between-individual variation in inter-limb thigh coordination was highest in early flight, while trunk-shank and shank-foot variation was highest in late flight, with a second peak in late stance for the trunk-shank coupling. There were clear step-to-step changes in coordination, with step 1 being distinctly different to subsequent steps. The results demonstrate that inter-limb coordination is primarily anti-phase and trailing leg dominant while ankle motion in flight and late stance appears to be primarily driven by the foot.
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Aceleración , Pie , Fenómenos Biomecánicos , Femenino , Humanos , Extremidad Inferior , Masculino , MusloRESUMEN
Rugby Union place kicking is influential to match outcome. Previous research has analysed kicker motion prior to ball contact in detail, but ball orientation and the impact phase are typically ignored. This study aims to firstly identify the ball orientations used by international place kickers, and secondly to experimentally analyse the foot-ball interaction in trained kickers using different ball orientations. Overall, 25.5% of the international kickers used an upright ball orientation, 27.5% used a diagonal orientation and 47.1% used a horizontal orientation. However, ball orientation preference was not significant in predicting kick outcome in a binomial logistic regression model. To address the second aim, ball orientation was experimentally manipulated and lower limb and ball kinematics were captured using high-speed (4000 Hz) video. Whilst the impact location on the ball differed significantly between most ball orientation conditions, the impact location relative to the global vertical was largely consistent across all conditions. This was likely due to kickers adopting very consistent lower limb kinematics, although the shank and ankle angles at impact were affected by ball orientation conditions for some kickers. Impact durations also differed between some conditions, although this did not appear to affect the impact efficiency.
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Light wearable resistance is used in sprint training but the scientific evidence to guide its implementation is limited. This study investigated thigh and shank loading protocols which were matched based on the average increase in moment of inertia about the hip over a stride cycle. Seven university-level sprinters completed three counterbalanced conditions (unloaded, shank-loaded, thigh-loaded), and kinematic variables were measured between 30 and 40 m. Both thigh and shank loading led to small reductions in step velocity (mean change = -1.4% and -1.2%, respectively). This was due to small reductions in step frequency (-1.8%; -1.7%) because of small increases in contact time (+2.7%; +1.5%) in both conditions and a small increase in flight time (+2.0%) in the shank-loaded condition. Both conditions led to moderate increases in hip extension at toe-off (+2.7°; +1.4°), whilst thigh loading led to a small reduction in peak hip flexion angle during swing (-2.5°) and shank loading led to a small increase in peak biceps femoris muscle-tendon unit length (+0.4%). Thigh and shank loading can both be used to provide small reductions in sprint velocity, and each has specific overload effects which must be considered in the rationale for their implementation.
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Carrera , Dispositivos Electrónicos Vestibles , Fenómenos Biomecánicos , Humanos , Extremidad Inferior , MusloRESUMEN
External peak power in the countermovement jump is frequently used to monitor athlete training. The gold standard method uses force platforms, but they are unsuitable for field-based testing. However, alternatives based on jump flight time or Newtonian methods applied to inertial sensor data have not been sufficiently accurate for athlete monitoring. Instead, we developed a machine learning model based on characteristic features (functional principal components) extracted from a single body-worn accelerometer. Data were collected from 69 male and female athletes at recreational, club or national levels, who performed 696 jumps in total. We considered vertical countermovement jumps (with and without arm swing), sensor anatomical locations, machine learning models and whether to use resultant or triaxial signals. Using a novel surrogate model optimisation procedure, we obtained the lowest errors with a support vector machine when using the resultant signal from a lower back sensor in jumps without arm swing. This model had a peak power RMSE of 2.3 W·kg-1 (5.1% of the mean), estimated using nested cross validation and supported by an independent holdout test (2.0 W·kg-1). This error is lower than in previous studies, although it is not yet sufficiently accurate for a field-based method. Our results demonstrate that functional data representations work well in machine learning by reducing model complexity in applications where signals are aligned in time. Our optimisation procedure also was shown to be robust can be used in wider applications with low-cost, noisy objective functions.