Alex Olmos1, Stephanie Sontag1, Sergio Perez1, Sunggun Jeon1, Shawn Allen1, Jeremy Lippman2, Michael Trevino1

1Oklahoma State University, Stillwater, Oklahoma; 2Univeristy of Kansas, Lawrence, Kansas

PURPOSE: To examine if 10-weeks of continuous cycling training altered pennation angle (PA) of the vastus lateralis (VL) in sedentary males and females. METHODS: Nine untrained males (mean ± SD; age: 20.11 ± 1.97 yrs, height: 179.89 ± 5.09 cm, body mass: 76.26 ± 8.18 kg) and eight untrained females (age: 20.50 ± 1.77 yrs, height: 164.13 ± 4.76 cm; body mass: 59.90 ± 8.33 kg) participated in this study. Fascicle PA (θ) of the VL was measured for each participant via real-time brightness mode (B-mode) ultrasonography at baseline (PRE) and after 10-weeks of continuous cycling training (POST). In addition, participants completed a VO2MAX test on an electronically braked cycle ergometer before (PRE) and after training (POST) to examine the efficacy of the exercise program on relative VO2MAX. Training consisted of 10-weeks of continuous cycling four times a week for a total of forty cycling sessions. Weeks 1-3 consisted of 30 min of cycling at 70-75% of heart rate reserve (HRR), whereas weeks 4-6 and 7-10 were 40 min at 75-80% and 80-90% of HRR, respectively. Three separate 2-way mixed factorial repeated measures ANOVAs (sex [male vs. female] x time [PRE vs. POST]) were used to examine potential differences in PA, VO2MAX, and body mass (BM). RESULTS: For PA, there were no two-way interactions (p = 0.189) or main effects for time (p = 0.635) or sex (p = 0.527). For VO2MAX, there was no two-way interaction (p = 0.904); however, VO2MAX for POST (45.45 ± 7.37 ml/kg/min) was significantly greater than PRE (39.22 ± 8.13 ml/kg/min; p < 0.001) when collapsed across sex, and was greater for males (47.59 ± 6.38 ml/kg/min) than females (36.54 ± 6.01 ml/kg/min; p = 0.001) when collapsed across time. For BM, there was no 2-way interactions (p = 0.400) or a main effect for time (p = 0.942); however, there was a main effect for sex. Males (76.46 ± 8.40 kg) had a greater BM than females (59.73 ± 8.20 kg; p = 0.001) collapsed across time. CONCLUSION: As expected, VO2MAXincreased following ten weeks of continuous cycling training. Although alterations in PA of the VL have previously been reported for chronic long-distance runners compared to untrained controls, there was no change following 10-weeks of training for the current study. Thus, it is possible more total training time is necessary to induce changes in the PA of the VL, or adaptations to PA are exercise mode specific.

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