Jump-landing mechanics in patellar tendinopathy in elite youth basketballers
- Authors: Harris, Meaghan , Schultz, Adrian , Drew, Michael , Rio, Ebonie , Charlton, Paula , Edwards, Suzi
- Date: 2020
- Type: Text , Journal article
- Relation: Scandinavian Journal of Medicine & Science in Sports Vol. 30, no. 3 (Mar 2020), p. 540-548
- Full Text: false
- Reviewed:
- Description: Patellar tendinopathy (PT) is a leading cause of morbidity in jump-landing athletes. Landing mechanics are identified as a factor associated with PT and/or patellar tendon abnormality. This study aimed to identify key jump-landing variables associated with PT. Thirty-six junior elite basketball players (men n = 18, women n = 18) were recruited from a Basketball Australia development camp. Three-dimensional (3D) kinematic and ground reaction force (GRF) data during a stop-jump task were collected as well as ultrasound scans of the patellar tendons and recall history of training load data. Mixed-model factorial analyses of variance were used to determine any significant between-group differences. Of the 23 participants included for statistical analyses, 11 had normal bilateral patellar tendons (controls) and eight reported PT (currently symptomatic); however, the four participants categorized as asymptomatic with patellar tendon abnormality on diagnostic imaging were excluded from statistical analyses due to their small sample size. Athletes with PT displayed a similar knee flexion angle at initial foot-ground contact (IC) and hip extension strategy during a stop-jump horizontal landing. Despite a similar kinematic technique, athletes with PT utilized a strategy of a longer stance duration phase from IC to peak force. This strategy did not lead to those athletes with PT decreasing their peak vertical GRF nor patellar tendon force during landing but enabled these athletes to land with a lower rate of loading (control 59.2 +/- 39.3 vs. PT 29.4 +/- 33.7 BW.s-1). Athletes with PT still reported significantly reduced training volume (control 4.9 +/- 1.8 vs PT 1.8 +/- 1.1 sessions/wk; total training time/wk control 2.4 +/- 1.0 vs PT 1.4 +/- 1.1 h/wk).
Caffeine, carbohydrate, and cooling use during prolonged simulated tennis
- Authors: Hornery, Daniel , Mujika, Inigo , Young, Warren , Farrow, Damian
- Date: 2007
- Type: Text , Journal article
- Relation: International Journal of Sports Physiology and Performance Vol. 2, no. 4 (2007), p. 423-438
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- Reviewed:
- Description: Purpose: To determine the effects of prolonged simulated tennis on performance and the ergogenic potential of caffeine, carbohydrates, and cooling. Methods: Twelve highly trained male tennis players (age 18.3 ± 3.0 y, height 178.8 ± 8.5 cm, body mass 73.95 ± 12.30 kg, mean ± SD) performed 4 simulated matches (2 h 40 min) against a ball machine on an indoor hard court. The counterbalanced experimental trials involved caffeine supplementation (3 mg/kg), carbohydrate supplementation (6% solution), precooling and intermittent cooling, and placebo control. Physiological markers (core temperature, heart rate, blood lactate, and blood glucose), subjective responses (ratings of perceived exertion and thermal sensation), stroke velocity and accuracy, serve kinematics, and tennis-specific perceptual skill quantified the efficacy of interventions. Results: Significant effects of time (P < .01) reflected increased physiological demand, reduced serve velocity and ground-stroke velocity and accuracy, and a slowing of the serve racket-arm acceleration phase. Caffeine increased serve velocity (165 ± 15 km/h) in the final set of the match (P = .014) compared with placebo (159 ± 15 km/h, P = .008) and carbohydrate (158 ± 13 km/h, P = .001) conditions. Carbohydrate and cooling conditions afforded physiological advantage (increased blood glucose, P < .01, and reduced preexercise thermal sensation, P < .01) but did not affect performance relative to the placebo condition. Conclusions: Prolonged simulated tennis induced significant decrements in tennis skills. Caffeine supplementation partly attenuated the effects of fatigue and increased serve velocity. In contrast, carbohydrate and cooling strategies had little ergogenic effect on tennis performance.
- Description: C1
- Description: 2003005648