Studies
Physiological responses to training using PowerCranks on trained cyclists
Stephen J. Dixon, Michael F. Harrison, Kenneth A. Seaman, Stephen S. Cheung and J. Patrick Neary University of New Brunswick, Fredericton, NB; Dalhousie University, Halifax, NS; University of Regina, Regina, SK
abstract
PowerCranks™ are cycling cranks that are independent of each other, requiring
force application throughout the pedal stroke, theoretically increasing muscle
recruitment and stimulus in the legs. This study examined the physiological
adaptations to PowerCranks, and the time course of responses in maximal and
submaximal cycling performance. Eight Trained cyclists (35.1 ± 6.8 yr)
participated in 6 wks of 100% immersion training using solely PowerCranks,
consisting of ~8 h/wk of aerobic and anaerobic (~80:20) cycling training. A
continuous incremental cycling test to exhaustion (50 W increase every 2 min)
was performed prior to and following the training program using normal cranks.
In addition, 10 min of submaximal cycling (70% of VO2max wattage) were
performed with both normal cranks and PowerCranks at an approximate cadence
of 85 rpm, pre and post training. VO2max increased 15.6% (58.1 ± 5.8 to 67.3 ±
6.6, P=0.013). Maximum power increased 11.6% (316.7 ± 25.8 to 358.3 ± 20.4,
P=0.011) following PowerCranks training. In summary, our data suggest that
PowerCranks increased maximal aerobic capacity and power in trained cyclists.
Effects of Short-Term Training Using Powercranks on Cardiovascular Fitness and Cycling Efficiency
Mark D. Luttrell,a and Jeffrey A. Potteiger
Department of Health, Sport and Exercise Science, University of Kansas, Lawrence, Kansas 66045
Department of Physical Education, Health and Sport Studies, Miami University, Oxford, Ohio 45056-3491
abstract
Powercranks use a specially designed clutch to promote independent pedal work by each leg during cycling. We examined the effects of 6 wk of training on cyclists using Powercranks (n = 6) or normal cranks (n = 6) on maximal oxygen consumption (O2max) and anaerobic threshold (AT) during a graded exercise test (GXT), and heart rate (HR), oxygen consumption ( O2), respiratory exchange ratio (RER), and gross efficiency (GE) during a 1-hour submaximal ride at a constant load. Subjects trained at 70% of O2max for 1 h·d−1, 3 d·wk−1, for 6 weeks. The GXT and 1-hour submaximal ride were performed using normal cranks pretraining and posttraining. The 1-hour submaximal ride was performed at an intensity equal to approximately 69% of pretraining O2max with O2, RER, GE, and HR determined at 15-minute intervals during the ride. No differences
were observed between or within groups for O2max or AT during the GXT. The Powercranks group had significantly higher GE values than the normal cranks group (23.6 ± 1.3% versus 21.3 ± 1.7%, and 23.9 ± 1.4% versus 21.0 ± 1.9% at 45 and 60 min, respectively), and significantly lower HR at 30, 45, and 60 minutes and O2 at 45 and 60 minutes during the 1-hour submaximal ride posttraining. It appears that 6 weeks of training with Powercranks induced physiological adaptations that reduced energy expenditure during a 1-hour submaximal ride.
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Road to Beijing with PowerCranks
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