Gabriel Brizuela

Supination control increases performance in sideward cutting movements in tennis

The objective of this study was to explore the effects of tennis shoe characteristics on performance during sideward cutting movements followed by direction changes. Five tennis players (age = 21.5 ± 0.8 years, mass = 75.2 ± 2.8 kg, and height = 1.78 ± 0.05 m) participated in the study and 10 tennis shoes were tested. Several footwear mechanical parameters were analyzed: Shore A hardness, longitudinal and transverse flexibility, midsole height at heel, presence of heel counters, and weight. A force plate was used to measure the kinetic variables, and two video cameras were used to perform a three-dimensional photogrammetric analysis. Results revealed that subject–footwear interaction was statistically not significant (p>0.05) for the kinetic and kinematic variables. Only contact time (p = 0.008) and supination movement (p = 0.009) were footwear dependent. Positive correlations between contact time and first supination peak (r = 0.783, p = 0.007) and second supination peak (r = 0.730, p = 0.016) were observed. Impulse was not changed, which means shoes limiting supination allowed tennis players to perform faster sideward cutting movements.

Influence of Training Load on Mood Disturbance at Sea Level and 3900 m Altitude: A Case Study of a Wheelchair Athlete

The purpose of this case study was to investigate the influence of a training load (TL), oxygen saturation (SO2) and blood pressure (BP) on mood states in a wheelchair marathoner during (7 weeks at sea level (SL), 5 weeks at 3860 m altitude, 1 week returning to SL). TL was obtained with Foster’s equation while mood states were obtained with the Profile of Mood States Questionnaire (POMS). Furthermore, SO2 and BP were assessed upon wakening. SO2 (%) decreased at altitude, compared to SL (88.31 ± 2.46 vs. 98.52 ± 0.11) and increased until the last week at altitude (92.64 ± 1.12). Systolic pressure (SP) increased at altitude compared to pre-altitude (126.0 ± 5.1 vs. 107.6 ± 4.4 mmhg), and was not different from the last week at altitude. Controlling for SO2 and SP, differences were also observed in fatigue (97.66 ± 18.92 vs. 17.39 ± 13.71) and vigor (73.23 ± 8.62 vs. 26.48 ± 11.89) as a function of altitude. Upon return to SL, fatigue, vigor, SO2 and SP returned to pre values. This case study demonstrated the POMS was sensitive to worsening patterns in fatigue and vigor at altitude through a practical survey approach combined with daily physiological assessment.