PowercranksTM are a device that enables the user to cycle with each leg acting independently of the other. This type of cycling forces the rider to actively pull up with the hip and knee flexors throughout the recovery phase of the pedaling cycle. While the metabolic benefits of training with PowercranksTM are known, no research has investigated what, if any, strength benefits result from training. The purpose of this study was to examine how strength, submaximal oxygen consumption, hear rate, gross efficiency, and muscle activation were affected by 6 weeks of PowercranksTM training, compared to a traditional cycling training. A total of 1 1 recreationally trained adult subjects (5 males, 6 females) were randomly placed into either the PowercranksTM group (PC) or regular cranks (RC) group. Subjects trained 3 days per week following a progressive interval protocol for 6 weeks. Prior to and following training, subjects were measured for peak isokinetic knee and hip flexion/extension strength, timing of muscular contractions, and submaximal VO2, heart rate, and gross efficiency. A MANOVA for strength values pre-post were not significant. However, large effect sizes implied that there were increases in knee and hip flexion for the PC group (d =1.00,1.63, respectively). Heart rate was found to be significant at all 4 time points (p = 0.001, 0.011, 0.001, 0.000 for time points 1-4, respectively). MANOVAs for VO2 and GE did not yield significant results. Muscular timing was also unchanged as a result of training. While the PowercranksTM did not have an effect on VO2 and GE in untrained subjects, HR decreased, suggesting an aerobic benefit. The possible strength benefits in untrained subjects resulting from PowercrankTM training could prove beneficial for individuals looking to recover from injury. / School of Physical Education, Sport, and Exercise Science

This study quantified the changes in pedaling mechanics and energy expenditure accompanying a posterior shift in cleat placement during prolonged cycling. Six male competitive cyclists participated. Each subject was asked to complete two separate hour long rides using traditional cleat placement and a novel heel placement, respectively. Expired gasses, kinematics, and EMG from 7 lower limb muscles were collected at three time intervals during each ride. No significant difference in O2 utilization was seen (p=0.905). A significant difference was seen in sagittal plane knee angle (p=0.008) and angular velocity (p=0.003) in the heel condition, demonstrating a more extended knee and lower peaks in angular velocity. Musculo-tendon kinematic data showed no differences. Tibialis anterior (TA) iEMG was higher in the heel condition, and SOL and TA showed differences in timing between conditions. These results demonstrate changes in ankling patterns and knee joint kinematics as adaptations to heel pedaling. / School of Physical Education, Sport, and Exercise Science

Graduation date: 1994

Background: Whole-body vibration (WBV) has been proposed as a viable alternative, or adjuvant to exercise for power development in athletes. More recently individualized frequency (I-Freq) has been introduced with the notion that individuals may elicit a greater reflex response to different levels (Hz) of vibration. Purpose: The aim of the study was to evaluate acute WBV as a feasible intervention to increase power in trained cyclists. Additionally, to evaluate the efficacy of utilizing I-Freq as an alternative to 30Hz, a common frequency seen in the literature. Methods: Twelve highly-trained, competitive male cyclists (age= 29.9 yrs ± SD 10.0; body height=175.4 cm ± SD 7.8; body mass= 77.3 kg ± SD 13.9) free of musculoskeletal injury or pathology participated in the study. The Wingate test for anaerobic power was administered on three occasions following a control of no vibration, 30 Hz, and I-freq. Measures of peak power (PP), average power (AP) and rate of fatigue were recorded and compared to the vibratory conditions using separate RM-ANOVA’s. Results: PP, AP, and rate of fatigue were not significantly impacted by 30 Hz and I-Freq vibration interventions (p > 0.05). Conclusion: Acute WBV using the parameters of the present study may not have been practical to elicit an increase in power as potential changes in the highly trained population may have been muted as a function of training status. / School of Physical Education, Sport, and Exercise Science