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THE INFLUENCE OF SPEED ON PATELLOFEMORAL JOINT KINETICS IN RECREATIONAL RUNNERS
Get PDFThis study aimed to determine the influence of running speed on patellofemoral joint (PFJ) kinetics. Twenty recreational runners ran on an instrumented treadmill at four running speeds with simultaneous 3D motion capture. A musculoskeletal model derived peak and cumulative (per 1km of continuous running) PFJ force and stress for each speed. Peak PFJ force and stress significantly increased with faster speeds. In contrast, cumulative PFJ measures decreased with faster speeds. Running at faster speeds increases the magnitude of peak PFJ kinetics but conversely results in less accumulated force over a set distance. Clinicians and coaches should be aware of the relatively high PFJ cumulative force and stress associated with slow running (~2.5 m/s) and consider moderate-speed interval running as part of overuse knee injury prevention and management plans
COMPARISON OF PEAK LUMBAR LORDOSIS BETWEEN SOME BASIC MOVEMENTS OF RHYTHMIC GYMNASTICS
Get PDFTo assist coaches in managing gymnasts, a good knowledge of the movements most likely to cause back pain is required. In rhythmic gymnastics (RG), this can be considered as identifying movements involving very high lumbar curvatures. To quantify the lumbar lordosis during some basic RG movements (ring, penché, penché with rotation, split leap, turning split leap, and front and back walkovers), eight gymnasts were enrolled and a 3D motion analysis was performed based on motion capture data, a musculoskeletal model and low-dose biplanar radiographs for model personalisation purposes. The ring and both the front and back walkovers were the movements studied involving the lumbar spine in extension the most but also resulting in the highest dispersion between gymnasts. Hence, future works should investigate the causes of this greater dispersion
THE RELATIONSHIP BETWEEN HORIZONTAL FORCE-VELOCITY PROFILE AND VERTICAL STRENGTH IN FEMALE ICE HOCKEY PLAYERS
Get PDFThe primary purpose of this study was to evaluate the horizontal force-velocity (HFV) profiles of female collegiate ice hockey players and compare these to metrics of muscular strength. The secondary purpose of this study was to categorize strength metrics using reduction analyses to improve the interpretation and application of these results and that of future studies. Thirteen female ice hockey players (body mass = 66.7±18.0 kg; height = 171.6±6.2 cm) completed three 50-meter on-ice sprints. Instantaneous velocity was measured using a radar gun in which participant HFV profile metrics (maximal velocity, tau, force-velocity slope, maximum theoretical force, ratio decrease force) were derived. Forty-eight hours later, participants completed four strength tests (drop jump, countermovement jump, loaded countermovement jump, and isometric squat) measured using a dual force plate resulting in 64 metrics of strength. A stepwise regression was employed to assess the associations between strength and HFV profile metrics. All strength metrics were entered into a principal component analysis (PCA) to support the interpretation of the results. There were no significant associations between strength and HFV profile metrics. The PCA identified four clusters of strength metrics that were considered distinct strength properties in this population. This study presents a robust method for evaluating skating HFV profiles and strength metrics in ice hockey players and should be used in future studies to contribute to this body of literature
LOAD-VELOCITY SLOPE CAN BE AN INDICATOR OF THE ACTIVE DRAG IN FRONT CRAWL SWIMMING
Get PDFThe purpose of this study was to investigate the relationship between swimming load-velocity slope and the active drag (Da) in front crawl. 19 female and 22 male swimmers were recruited and performed three 25 m front crawl sprints with different external loads (1, 3, 5 kg for females and 1, 5, and 9 kg for males) assigned by a robotic resistance device. The mean swimming velocity was plotted against the external load to establish the load-velocity profile for each swimmer. Da was obtained by the velocity perturbation method. The relationship between the load-velocity slope and Da was assessed using the Pearson correlation coefficient, which showed a very large correlation (r = 0.84, p \u3c 0.001) and an extremely large correlation (r = 0.93, p \u3c 0.01) for female and male swimmers, respectively, indicating that the load-velocity slope is an indicator of Da in front crawl swimming
IMU PHASE-BASED PERFORMANCE EVALUATION SENSITIVITY TO THE PROGRESS OF YOUNG FRONT CRAWL SWIMMERS
Get PDFThe aim of this study was to evaluate the sensitivity of a phase-based performance assessment method obtained from a sacrum IMU to assess swimming progress. Five IMU-based goal metrics were extracted from the literature for the main swimming phases of wall push-off, glide, strokes preparation, swim, and total lap. Sixteen young competitive swimmers completed five one-way front crawl laps at maximum speed with an IMU attached to the sacrum while the coach recorded lap time as the main indicator of performance level. To monitor the swimmers\u27 performance improvement, the same test was repeated once a week for 10 weeks. The minimum 0.5s change in lap time was calculated as the minimum worthwhile enhancement. The results showed that the goal metric of whole lap and swim phase closely predict swimming progress (e.g., accuracy, precision, sensitivity, and specificity of 0.91, 0.89, 0.94, and 0.95 for the whole lap goal metric, respectively). Other goal metrics achieved high precision and specificity (≥ 0.79) for detecting the progress, indicating that they can be reliably used for further improvement of swimmers in the level of swimming phases. The results showed that coaches can use the goal metrics in training sessions to track the progress of the swimmers in each phase
EFFECTS OF RUNNING HABITS ON MORPHOLOGY AND PLANTAR FLEXION TORQUE OF MEDIAL GASTROCNEMIUS-ACHILLES TENDON UNIT
Get PDFThis study aims to explore the effects of running habits on the morphology of gMTU (medial gastrocnemius-Achilles tendon unit) and plantar flexion torque, to reveal the adaptive changes of different running habits. Male habitual distance runners with forefoot strike pattern (FFS, n=10), male habitual distance runners with rearfoot strike pattern (RFS, n=10), and male non-runners (NR, n=10) were recruited. The Mindray M7 Super ultrasonography system was used to measure the morphological characteristics of the gMTU. A dynamometer was utilized to determine the plantar flexion torque. One-way ANOVA and Nonparametric Test were used for analysis. The significance level was set as 0.05. Significant differences between groups were detected on muscle fascicle length (FL) (p \u3c 0.05), Normalized FL (p \u3c 0.05), and pennation angle (PA) (p \u3c 0.01), while no significant difference was observed in other parameters. Specifically, the FL and Normalized FL were greater in FFS than NR (p \u3c 0.05), while the PA was smaller in FFS than NR (p \u3c 0.05). These results suggest that long-term running with FFS pattern could induce a greater contraction velocity and a more efficient force transmitting of the medial gastrocnemius (MG)
CITATIONS TO BIOMECHANICS ARTICLES FROM FOUR DATABASES
Get PDFFour (Dimensions, Google Scholar, Scopus, Web of Science) multi-disciplinary databases were searched for journal articles published by one scholar to document the coverage of exercise and sports biomechanics. Cleaned searches returned 65 to 93 articles in common between these databases from 116 journals articles published between 1989 and 2019. Citations and mean citation rates were qualitatively higher for Google Scholar (3206 & 3.2) than the other three databases (1100-1400 & 1.6-2.1). Strong positive correlations (0.88-0.96) of citations between databases indicated that for this case, study citations from subscription databases (Scopus & Web of Science) could be predicted (SEE 3 to 7) from the free databases (Dimensions and Google Scholar). This case study indicated incomplete coverage and subtle inconsistences are likely between these databases in exercise and sport biomechanics. Skillful searching of multiple databases is recommended
CHARACTERISING LONGITUDINAL ALTERATIONS IN POSTURAL CONTROL FOLLOWING LOWER LIMB INJURY IN PROFESSIONAL RUGBY UNION PLAYERS
Get PDFAssessment of player’s postural control following a lower limb injury is of interest to sports science and medicine practitioners due to its fundamental role in daily tasks and sporting activities. The purpose of this study was to measure the longitudinal changes in rugby union player’s postural control throughout return to play (RTP) following lower limb injury. Rehabilitation was divided into three phases – acute, middle and late. Nine players from a professional rugby union team (height 1.80±0.06 m; mass 96.1±13.2 kg; age 25±3 years) were included in this study. Static unilateral postural control was measured in the acute phase using a PASCO dual axis force platform (PS-2142). Dynamic postural control was measured using single axis PASCO force platforms (PS-2141) with the middle phase being assessed by unilateral drop jump and the late phase a unilateral lateral hurdle hop. During the acute phase, no improvement were observed between the initial testing session and end testing session, nor any differences between the end of the acute rehabilitation phase and pre-injury baseline. Whereas for the middle and late phase improvements were observed between the initial and end testing session, with smaller magnitudes of dynamic postural control adjustment (DPCA; p (
EFFECTS OF AN 8-WEEK KNEE INJURY PREVENTION PROGRAM AND TECHNIQUE MODIFICATION TRAINING ON CHANGE-OF-DIRECTION PERFORMANCE
Get PDFThe purpose of this analysis was to determine whether an 8-week knee injury prevention program with an additional focus on change-of-direction (COD) technique training results in improved COD performance compared to a control training group with a focus on linear sprint training. Although both groups showed indicators for superior performance during a 135-degree COD, such as a more effective reorientation of the body, the COD technique modification component was ineffective in improving overall COD completion time or ground contact times. Follow-up analyses will show whether the COD group adopted a safer COD movement strategy following training, e.g. by reducing the knee valgus loading
A BIOMECHANICAL INVESTIGATION OF A SPANISH SQUAT: THE EFFECT OF TRUNK INCLINATION AND LOAD ON QUADRICEPS ACTIVITY AND PATELLAR TENDON FORCE
Get PDFThe Spanish squat targets the knee extensor muscles and has been suggested to be an appropriate rehabilitation exercise for patellar tendinopathy. This study provides novel empirical data on the effect of trunk inclination and load on quadricep muscle activity and patellar tendon load while performing the Spanish squat. The findings of this study informs on the progression and regression of the Spanish Squat and provides evidence to support the application of the Spanish squat in progressive tendon loading strategies in the treatment of PT