5954 research outputs found
Sort by
EXTRA CREDIT AND PERCEIVED STUDENT ACADEMIC STRESS
Get PDFThis article examines the impact of extra credit availability on students’ perceived stress. The study looks at two areas. First, what type of extra credit students prefer be made available. Second, how student academic stress is impacted by the availability of extra credit. Results show that undergraduate business students at a private university prefer merit based extra credit and that perceived academic stress is higher for students when extra credit is available. Stress is particularly high for higher-performing students
Maintenance of dynamic single-legged stability with delayed peroneal reaction time in collegiate footballers during a prolonged football simulation
Get PDFThe purpose of this study was to examine the change of peroneal reaction time and dynamic single-legged stability during a prolonged football match simulation. 12 collegiate footballers participated a Loughborough intermittent shuttle run protocol, within which peroneal reaction time and dynamic single-legged stability were measured to record the change. Results showed that during a prolonged fatiguing protocol, the peroneal reaction time increased significantly, whereas two indicators of the dynamic single-legged stability, root mean square of the mediolateral ground reaction force in 0.4 second of landing and late dynamic mediolateral ground reaction force, remained unchanged. The outcome indicated that the body might adopt different mechanism to maintain sensorimotor control in fatigue state
MOTOR ENTROPY INFLUENCE ON SPORT RESULTS: USAIN BOLT\u27S RECORD-BREAKING RACE EXAMPLE
Get PDFThe purpose of this study was to estimate Usain Bolt\u27s motor entropy and to calculate its effect on athletic performance. The paper analyzes momentary velocity for Usain Bolt in the men’s 100 m final at the 2009 IAAF World Championships. Applied to results in cyclic sports, motor entropy depends on the ability to reproduce the most effective running stride. Any variations negatively affect to sports performance and lead to increasing of entropy. We identified Shannon entropy for peaks (4.5 bit) and troughs (2.9 bit) of intracyclic velocity. Numerical simulation of momentary velocity with zero entropy shows that Usain Bolt’s time could be 9.42 s instead 9.58 s. Zero entropy means absolute body control without technique inaccuracies and full realization of the motor potential. Motor entropy is one of the factors that determine athletic performance
MULTI-SEGMENT CONTRIBUTIONS TO INDUCED BALL VELOCITY IN COLLEGIATE BASEBALL PITCHERS
Get PDFThe purpose of this study was to implement an induced acceleration analysis (IAA) to estimate the contributions of multi-segment motion to the forward velocity of the ball in collegiate baseball pitchers. Marker-based motion capture and ground reaction force data were collected from a sample of 17 pitchers throwing off an instrumented mound. Kinematic and kinetic data were extracted to drive the IAA model to calculate the muscular and non-muscular contributions to ball velocity. The shoulder joint torque and velocity-dependent torque collectively made up the largest contribution to the total induced velocity of the ball at 61% and 37%, respectively. The model underestimated ball speed by 16%, owing to limitations in distal segment definitions. Although this IAA showed that the proximal segments make a small, direct contribution to forward ball velocity, decomposition of the velocity-dependent torque could further clarify the extent to which the legs, pelvis, and trunk indirectly contributes to ball velocity
VERTICAL POWER-FORCE-VELOCITY PROFILING: RELIABILITY COMPARISON OF MULITPLE- AND TWO-POINT METHODS
Get PDFPower-Force-velocity (P-F-v) profiling is an approach used for performance diagnostics to assess an athlete’s anaerobic performance level. The aim of the study was to determine and compare the test-retest reliability of the 5p-method and the 2p-method for a group of sport students. With respect to the 2p-method this was the first study to determine the reliability using an independent data-set for vertical jumps. Acceptable reliability (ICC \u3e 0.78, CV \u3c 7.6%, no significant differences) was obtained for the variables F0, v0 and Pmax obtained through the 5p-method. Using the 2p-method acceptable reliability was just found for the variables F0 and Pmax. Therefore, the use of the 5p-method is recommended for performance diagnostics and derived individualized training regimes based on these P-F-v profiling results, as well as for research on this topic involving populations similar to sport students
THE PRE-EXHAUSTION METHOD SEEMS INEFFECTIVE TO INCREASE ELECTROMYOGRAPHIC ACTIVITY
Get PDFThe purpose of this study was to investigate the effects of the pre-exhaustion method on the electromyographic activity (temporal and spectral domain) at different intervals of a set of resistance training. Twenty adults with little or no experience in strength training performed two sets of the seated row exercise at 70%1RM until muscular failure, in a randomized order. Surface electrodes were placed over the latissimus dorsi, teres major, biceps brachii, and posterior deltoid muscles of the dominant side. Results showed that the pre-exhaustion did not increase EMG activity of all muscle analyzed at any intervals of a set. Furthermore, the EMG median frequency decreased in teres major and posterior deltoid muscles during initial and intermediate repetitions. Results suggest that the pre-exhaustion induces more fatigue when compared to traditional training
THE RELATIONSHIP BETWEEN HAMSTRING INJURY RISK SCREENING TESTS AND LOWER LIMB BIOMECHANICS DURING SPRINT
Get PDFThe purpose of this study was to explore the relationship between hamstring injury risk screening test scores and lower limb biomechanical characteristics during sprint, and to select more appropriate screening tests from the perspective of biomechanics. Soccer players(n=18) experienced three kinds of hamstring injury screening tests(Nordic hamstring test, ultrasound test, straight-leg-raising test) and collected kinematics data and dynamics data of the lower extremities during sprint. The result of the Nordic Hamstring Test was significantly positively correlated with the peak force of semimembranosus muscle, semitendinosus muscle and biceps femoris long head during sprint (