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KINEMATICS CHANGE IN COUNTERMOVEMENT JUMPS WITH ADDITIONAL LOADS
Get PDFThe aim of this study was to investigate the effect of sex and additional load during countermovement jumps on hip, knee, and ankle joint kinematics. For this purpose, a total of 25 female and male participants performed barbell-loaded countermovement jumps with up to 80% of body mass. No significant main effect of sex on any of the kinematic parameters was found. The additional load resulted in a significant decrease in hip, knee, and ankle joint angles in the sagittal plane and an increase of the absolute performance time. Significant differences were also found in the frontal and transverse plane kinematics. Hence, since changes in kinematics of all three anatomical planes could increase the risk of injury, they should be closely monitored
THE EFFECTS OF BLOOD FLOW RESTRICTION ON MEASURES OF GROSS MOTOR COORDINATION DURING THE WINGATE ANAEROBIC TEST
Get PDFTo date little research has addressed the impact of blood flow restriction (BFR) training upon gross motor coordination measures (GMCM) during a wide variety of maximal activities. The purpose of this study was to assess the effects of BFR on GMCM exhibited during maximal cycling. The performance of 14 females between the ages of eighteen and thirty-five were analyzed during the Wingate Anaerobic Test (WAnT). The participants completed the test under two conditions, using BFR and without. Results showed statistically significant differences (p ≤ 0.05) between conditions for dependent variables assessed throughout this common 30 second test of maximal cycling. These findings suggest that BFR negatively influenced GMCM exhibited during the WAnT
HUMERAL RETROVERSION, CORRECTED RANGE-OF-MOTION, AND FAST SCORES IN COLLEGIATE BASEBALL PITCHERS
Get PDFThe purpose of this study was to examine the relationship between shoulder rotational range of motion, accounting for humeral retroversion (HR) and the Functional Arm Scale for Throwers (FAST). Nineteen male NCAA Division I collegiate baseball pitchers participated in the study and completed a modified FAST form. Humeral retroversion was measured and total rotational range of motion, corrected internal rotational range of motion, and corrected external rotational range of motion were calculated. No relationships were found between rotational ROM and the FAST score. The findings suggest further research needs to be performed on patient reported outcomes specific to changes in rotational ROM
INVESTIGATING KEY FACTORS FOR FEMALE PLAYERS TO GENERATE COMPARABLE INTERACTION TORQUE TO THAT OF MALE PLAYERS
Get PDFWe aimed to clarify the kinetic strategy of female players to achieve comparable motion-dependent interaction torque to that of male players during soccer instep kicking. The kicking leg motion of female and male players was captured at 500 Hz. The interaction torque was decomposed into two components due to the kicking leg and the support leg actions using the procedure of Inoue et al., (2013). Female players exhibited significantly smaller counter-clockwise (positive) interaction torque due to the support leg action while the clockwise (negative) component due to the kicking leg action was significantly suppressed in the latter part of kicking than male players. Our findings suggest coaches and female players should pay more attention to the kicking leg posture during the latter part of the leg swing to maintain their effective action of the interaction torque
KNEE JOINT LOADS AND ASSOCIATION BETWEEN KNEE JOINT LOADS AND KNEE FLEXION ANGLE DURING A FORWARD LANDING TASK IN PEOPLE WITH AND WITHOUT CHRONIC ANKLE INSTABILITY
Get PDFThe purpose of this study was to compare the knee joint loads (forces and impulse), compare muscle contribution to knee joint loads, and examine associations between knee flexion angle and knee joint loads during a forward jump-landing task in people with chronic ankle instability (CAI). Eight people with CAI and eight healthy controls performed forward jump-landings. Kinetics and kinematics were calculated using musculoskeletal modelling. There was no significant difference in knee joint loads and muscle contributions between groups. However, there were significant associations between knee flexion angle and knee anteroposterior force and impulse for each group separately and all participants combined. Our results may indicate that while CAI does not affect the knee joint loads, greater knee flexion angles may increase knee loading
REAL-TIME BACKWARD SLIP DETECTION USING A SLIP-INDUCING SYSTEM AND MACHINE LEARNING METHODS
Get PDFWearable devices have been developed to assist walking based on the wearer’s intention. However, it would be dangerous if a device misidentifies falling as intentional motion; it is necessary to detect falls in real time. In particular, backward slip is the most common and dangerous type of falls. Fifteen participants walked on a split-belt instrumented treadmill while random backward slip perturbation of belt speed acceleration was provided to the foot. We aimed to identify slip within 0.35s after the onset of the perturbation, the typical window of slip, using lower limb kinematic data obtained within 0.3s; only 0.05s was allowed for the identification. We developed 5 machine learning models, and the logistic regression model showed the highest accuracy of 87.5%. The initial study is expected to contribute to the prevention of falls by developing and applying the results to wearable devices
EVALUATING THE EFFECTIVENESS OF AN INJURY PREVENTION WARM-UP FOR FEMALE COLLEGIATE SOCCER PLAYERS
Get PDFNeuromuscular training programs have been shown to decrease injury risk. The purpose of this study was to determine the effectiveness of a soccer-specific injury prevention warm-up program at improving game-time movement patterns. Acceleration and gyroscope data from IMUs and foot forces from smart insoles were collected in-the-field from 16 players during regularly scheduled soccer practice sessions. Change in impact and tibial anterior shear force, and lower extremity kinematics were compared throughout the season with a MANOVA. Tibial anterior shear force and acceleration, knee extension, and knee valgus decreased within each training session (Λ = 0.387, F18,75 = 12.65, p \u3c 0.01), but not across the season (Λ = 0.913, F5,18 = 0.34, p = 0.879). This injury prevention warm-up program may be effective at modifying ACL injury risk factors in the short-term but not the long-term
The Influence of Court Surfaces on Lower Limb Muscle Activation of Tennis Run-and-Stroke
Get PDFThis study aimed to examine the characteristics of lower extremity muscle activity between different tennis court surfaces. Six male right-handed elite tennis players were recruited, and their electromyography activity (EMG) during open stance running forehand were collected. Average activity level of rectus femoris (RF), biceps femoris (BF), gastrocnemius (GAS), tibialis anterior (TA) from the lead leg, which normalized by maximal voluntary isometric contractions (MVC) was recorded under different situation (hard court, grass court, clay court). Our study demonstrates that GAS was significantly different and the activation level was greater on a hard court than on clay (p = .005). Tennis players should enhance their gastrocnemius muscle performance when matching from clay to hard court to avoid a higher level of gastrocnemius activation when adapting to a different court, which could lead to an injury.
KEYWORDS: Grand Slam, training, EMG, performanc
”SUPER SPIKES” INCREASE 40-M SPRINT PERFORMANCE IN NATIONAL-LEVEL WOMEN ATHLETES
Get PDFThe aim of this work was to quantify the effect of adding carbon fiber plates in the midsole of spike shoes (i.e., super spikes ) on 40-m sprint performance. Eight female national level athletes completed four 40-m sprints using two different types of footwear (i.e., traditional spikes and “super spikes”). The main results showed an improvement of 0.6% in performance when the athletes wore super spikes (i.e., 0.031 s in 0-40 m), mainly in the flying phase (i.e., 0.026 s in the 20-40 m), which could be due to an increase in leg and vertical stiffness (i.e., greater in the super spikes ) and a reduction in the ground contact time (i.e., less time with “super spikes”). Also, this improvement seems to be related to the sprinter’s performance level. In conclusion, wearing super spikes has a positive effect on 40-m sprint performance compared to conventional spikes
EVALUATING THE COMBINED EFFECT OF NECK MUSCLE STRENGTH AND HOCKEY GOALTENDER HELMET LINERS IN MITIGATING CONCUSSION RISK DURING SIMULATED HORIZONTAL HEAD IMPACTS
Get PDFConcussions represent the second most common injury for ice hockey goaltenders. This study examined the combined effect of neck strength level and helmet liner type in mitigating concussion risk for ice hockey goaltenders. The researchers tested each helmet liner material statically for energy absorption capacity of the liner material, and dynamically by recreating concussion-causing events via head impact simulations for the risk of head injury criterion (HIC). The thermoplastic polyurethane (TPU) liner outperformed the standard vinyl nitrite (VN) liner during static testing and significantly reduced the HIC for high levels of neck strength (in newtons) during the repeated impact testing at the front, side, and back locations of the helmet. This information may facilitate the development of helmet liners composed of TPU and VN material across a range of neck strength levels to mitigate concussion risk for goaltenders