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NEUROMUSCULAR AND MUSCLE MORPHOLOGICAL ADVANTAGE OF POWER-TRAINED ATHLETES IMPROVES HIP EXTENSION TORQUE AT HIGH VELOCITIES
No full textThe purpose of this study was to examine the intermuscular distribution of hamstring muscle volume, muscle excitation, and torque production capacity of hip extensors in power-trained (sprint-based) athletes compared to a strength-trained control group. We found higher semitendinosus volume in the power-trained group. The electromyography activity increased with increasing contraction velocity only in the power-trained group, with significant between-group differences observed in the semitendinosus and biceps femoris at high velocity hip extension. Power-trained athletes were stronger during concentric contractions, particularly at high contraction velocities. These results explain possible morphological and neuromuscular mechanisms to increase propulsive force in high-speed running, which should be considered when designing training for sprint-based athletes
CAN A NEW RULE ADAPTED TAKEOFF ZONE IMPROVE APPROACH-RUN AND TAKEOFF MOTIONS IN LONG JUMP?
No full textThe aim of this study was to clarify the effect of implementing the new long-jump rule with a takeoff zone, which is currently proposed by World Athletics, on the approach-run and takeoff movements. Ten male collegiate jumpers specializing in horizontal jumping events participated in the experiment. The main finding was no significant difference of effective distances was observed between the proposed and conventional trials. This may due to the fact that no significant differences of maximal horizontal center of mass (COM) velocity, horizontal COM velocity at the landing of takeoff, and takoff angle were observed between the proposed and conventional trials.Therefore, this proposed rule change is expected to only avoid fault trials where athletes touch the ground beyond the take-off line in long jump
DEVELOPMENT AND VALIDATION OF AN ALGORITHM FOR FOOT CONTACT DETECTION IN HIGH-DYNAMIC MOVEMENTS USING INERTIAL MEASUREMENT UNITS
No full textWearable IMUs offer a promising alternative to lab-based motion capture for sports biomechanics. Accurate foot contact detection (FCD) is crucial, yet most algorithms are validated for daily activities, leaving a gap in high-dynamic movements, such as sprints and changes of direction, which are linked to injury risk. This study (I) reviews FCD algorithms for such tasks and (II) develops a new IMU-based algorithm for detecting initial contact (IC) and toe-off (TO). The review highlighted limitations in sport-specific FCD solutions. Two algorithms using Pelvis Vertical Velocity (PVV) and Resultant Foot Acceleration (RFA) were tested on 302 trials. A hybrid approach combining the two, improved accuracy, achieving 5.6ms and 20.4ms median offsets for IC and TO detection respectively. The final algorithm, validated against force plates, offers a valid method for real-world sports applications
DEVELOPMENT OF SPRINT RUNNING PERFORMANCE OVER 4 YEARS: A CASE STUDY
No full textThe purpose of this study was to identify changes in the kinematics and kinetics of sprinting through the development of sprint performance in a male sprinter over four years. In the experiment, a male sprinter performed a 60-m sprint during which ground reaction forces and running motion were measured using a long force platform system and a motion capture system, respectively. The participant improved his 200-m personal record by 1.17 s over the four years. The characteristics of changes in the kinematics and kinetics of sprinting varied across the years. A decrease in knee extension torque during the support phase and an increase in ankle plantarflexion torque during the support phase were consistent throughout the development of maximal sprinting speed. These characteristics could serve as directions for training to improve sprint performance
THE EFFECT OF BASEBALL BAT DIAMETER ON BATTED BALL
No full textThe purpose of this study was to investigate the effect of bat diameter on the batted ball characteristics in baseball. A custom-made bat swing machine swung bat horizontally and hit a ball floating in the air using wind pressure. Three bats of different diameter (6.30 cm, 5.73 cm, and 5.32 cm) were used with 30 trials per bat. Three high-speed video cameras were used to record the movements of the bat and ball near the impact and compared the batted ball characteristics. As a result, bat diameter did not appear to have a significant effect on batted balls
THE EFFECT OF (ACCELERATION-DECELERATION) EXERCISE WHITH MODERATE INTENSITY IN SMALL SPACES ON THE STRENGTH OF HAMSTRINGS IN FOOTBALL PLAYERS
No full textThe purpose of this study is to examine the effect of acceleration-deceleration exercise in small spaces on the strength of the hamstring muscle and ideally prevent it from a possible injury. A significant number of previous studies have shown that the negative effect of exercises using acceleration and deceleration on hamstring injury is due to the maximum use of intensity. Instead, in this study we have used moderate intensity in small spaces. on The idea was that acceleration-deceleration exercises have the same mechanism of contraction(contracting and extending) with strength training despite the different way they function, and through that development of strength we can prevent the hamstring muscle from injury. A training program was composed of 12 sessions using a preliminary data set(n=12) and an experimental approach . The results showed that these exercises have unclear effects on hamstring strength but they could contribute potential prevention of hamstring injur
SURFACE CONDITION MEASUREMENT FOR RUNNERS USING SMARTPHONE SENSORS
No full textCurrent running platforms lack quantitative surface characterization despite its critical influence on performance and injury risk. We developed a smartphone-based method using ankle-mounted inertial sensors to measure runner-surface interactions through two metrics: Runner-Perceived Hardness Index (RPHI) and Runner-Perceived Traction Index (RPTI). Two runners performed total of 19 analyzable trials across cement and snow surfaces. Results show cement had a significantly higher RPHI (15.32±5.53 vs. 1.94±1.12 m/s²) and a significantly lower RPTI (16.52±2.17 vs 25.00±3.35 m/s²) than snow. These findings validate smartphones for real-time surface characterization, enabling data-driven training optimization previously limited to laboratories
A STUDY ON MECHANICAL CHANGES DURING THE MIDDLE PHASE OF THE LONG JUMP APPROACH RUN
No full textThis study investigated the mechanical adjustments made by elite long jumpers during the middle phase of the approach run. Kinematic data from the 5 senior Indian national level long jumpers (Personal Best:7.83±0.63m) with five high speed cameras (at resolution 1920s1080 with 120 frame per second). Further all the motion were quantified with Quintic (v.33). It was revealed that athletes maintained consistent step lengths while introducing subtle variations to manage velocity effectively. Study observed, some changes in torso touch-down angles; especially at 4LS were observed, indicating conscious efforts to optimize control without sacrificing step length. Contact duration (CD) varied across individuals, with athletes such as P1 and P4 increasing CD at 5LS and reducing it at 4LS, suggesting a dynamic modulation of ground contact to regulate approach velocity. The maximum knee angle during support influenced centre of mass lowering, potentially compromising velocity for take-off preparation. Despite individual differences, all athletes showed a gradual decrease in velocity, highlighting a controlled transition into the final steps. Overall, step length, knee angle, torso angle, and CD were closely linked to the athletes’ aim of achieving optimal velocity before take-off
EXPERTISE AND COORDINATION IN SHOW JUMPING: INVESTIGATING LUMBAR MOTION
No full textThe objective of this study was to evaluate the influence of expertise on the coordination between the rider and their horse during the approach and reception phases in show jumping. Sixteen riders, divided into two groups (professionals, n=8; amateurs, n=8), performed a show jumping task while their movements were recorded using IMUs (XSens MVN) placed on them and on their horse’s sternum. The rider’s lumbar orientation (L3) and the horse’s sternum orientation were analysed to quantify coordination using continuous relative phase (CRP). Statistical analysis using Statistical Parametric Mapping (SPM) highlighted significant expertise-related differences at specific moments within the stride cycle. In professional riders, lumbar extension is weaker and their movement is in advance of the horse\u27s movement suggesting enhanced anticipatory control
RELATIONSHIP BETWEEN SWIMMING VELOCITY AND FOOT KINEMATIC CHARACTERISTICS IN NOVICE BREASTSTROKE SWIMMERS
No full textThe study aimed to examine the relationship between the swimming velocity (SV) and the kinematic characteristics of the foot in novice breaststroke swimmers. Six novice male swimmers participated in the study. Participants performed two prone 10 m breaststroke kick trials on a kickboard. The kicking movements were recorded with two synchronized underwater cameras, and a three-dimensional analysis of the right-side kicking motion was conducted. The results revealed that significant negative correlations were found between the SV during a single breaststroke kick cycle and both the longitudinal and lateral kick widths (r = -.943, P \u3c 0.01; r = -.886, P \u3c 0.05). Moreover, a significant correlation was observed between the internal rotation angle of ankle joint in the insweep phase and SV (r = .886, P \u3c 0.05), These findings suggest that novice breaststroke swimmers should avoid an excessively wide lateral kick, and greater ankle internal rotation in the insweep phase to enhance their kicking performance. However, given the small and homogeneous sample in this study, caution is warranted when generalizing the findings