Three-dimensional kinematic correlates of ball velocity during maximal instep soccer kicking in males.

Achieving a high ball velocity is important during soccer shooting, as it gives the goalkeeper less time to react, thus improving a player's chance of scoring. This study aimed to identify important technical aspects of kicking linked to the generation of ball velocity using regression analyses. Maximal instep kicks were obtained from 22 academy-level soccer players using a 10-camera motion capture system sampling at 500 Hz. Three-dimensional kinematics of the lower extremity segments were obtained. Regression analysis was used to identify the kinematic parameters associated with the development of ball velocity. A single biomechanical parameter; knee extension velocity of the kicking limb at ball contact Adjusted R(2) = 0.39, p ≤ 0.01 was obtained as a significant predictor of ball-velocity. This study suggests that sagittal plane knee extension velocity is the strongest contributor to ball velocity and potentially overall kicking performance. It is conceivable therefore that players may benefit from exposure to coaching and strength techniques geared towards the improvement of knee extension angular velocity as highlighted in this study.

Biomechanical differences between experienced and inexperienced wheelchair users during sport.

BACKGROUND: During functional wheelchair movement there are several types of stroke pattern that a manual wheelchair user (MWCU) can utilize in order to propel. OBJECTIVES: To examine the biomechanical differences between disabled (WCU) and able-bodied (NWCU) children whilst taking part in functional activities at the Cheetahs Wheelchair Sports Club. STUDY DESIGN: A multiple measures cohort study. METHODS: Eleven participants were divided into two groups; WCU (n = 7) and NWCU (n = 4). All subjects were asked to perform three functional tasks; 30-second agility test, 1-minute distance test and a 10-metre sprint test. Upper body kinematics were recoded using a XSens MVN BIOMECH motion capture suit. RESULTS: NWCU outperformed the WCU in all of the tasks, however, no significant differences between the group's results were found. Nevertheless, significant differences were found in the maximum shoulder flexion angle for both right and left with NWCU utilizing more flexion and near significant differences in the NWCU overall shoulder range for right and left. CONCLUSIONS: In order to increase function in young MWCU then more specific-based sessions should be implemented targeting the exploitation of large shoulder ranges during propulsion, consequently resulting in more efficient movement.

The effects of carbohydrate ingestion on the badminton serve after fatiguing exercise.

The badminton serve requires great skill and may be affected by fatigue. The aim of the present study was to determine whether carbohydrate ingestion affects badminton performance. Nine male badminton players (age 25 ± 7 years, mass 80.6 ± 8.0 kg) attended the laboratory on three occasions. The first visit involved an incremental exercise test to exhaustion to determine peak heart rate. Participants were given 1 L of a carbohydrate-electrolyte drink or a matched placebo during the experimental trials. The accuracy of 10 long and 10 short serves was determined before and after exercise. The fatiguing exercise was 33 min in duration (83 ± 10% and 84 ± 8% peak heart rate for the placebo and carbohydrate trial respectively). Capillary blood samples (20 µL) were taken before and after exercise for determination of blood glucose and lactate. There was deterioration in long serve accuracy with fatigue (P = 0.002), which carbohydrate ingestion had a tendency to prevent (P = 0.077). There was no effect of fatigue (P = 0.402) or carbohydrate ingestion (P = 0.109) on short serve accuracy. There was no difference in blood glucose concentration between trials (P = 0.851). Blood lactate concentration was higher during the placebo trial (P = 0.016). These results suggest that only the long serve is influenced by fatigue and carbohydrate had a tendency to prevent the deterioration in performance.