Influence of Bicycle Seat Tube Angle and Hand Position on Lower Extremity Kinematics and Neuromuscul
I was being a geek and poking around in PubMed today and found this. If you want the full article, send me a PM.
J Appl Biomech. 2011 Jul 29. doi: . [Epub ahead of print]
Influence of Bicycle Seat Tube Angle and Hand Position on Lower Extremity Kinematics and Neuromuscular Control: Implications for Triathlon Running Performance.
Silder A, Gleason K, Thelen DG.
Source
Department of Biomedical Engineering, University of Wisconsin - Madison, Madison, WI.
Abstract
The purpose of this study was to characterize differences in muscle kinematics and activation patterns between cycling and running. We then investigated how varying seat tube angle (STA) and hand position affect muscle kinematics and activation patterns to better understand how triathlon-specific bike geometries might mitigate the biomechanical challenges associated with the bike-to-run transition. Whole body motion and lower extremity muscle activities were recorded from fourteen triathletes during a series of cycling and treadmill running trials. A total of nine cycling trials were conducted in three hand positions (aero, drops, hoods) and at three STAs (73º, 76º, 79º). Participants also ran on a treadmill at 80, 90 and 100% of his/her 10kmtriathlon race pace. Compared to cycling, running necessitated significantly longer peak musculotendon lengths from the uniarticular hip flexors, knee extensors, ankle plantarflexors, and the biarticular hamstrings, rectus femoris, and gastrocnemius muscles. Running also involved significantly longer periods of active muscle lengthening from the quadriceps and ankle plantarflexors. During cycling, increasing STA alone had no affect on muscle kinematics, but did induce significantly greater rectus femoris activity during the upstroke of the crank cycle. Increasing hip extension by varying hand position induced an increase in hamstring muscle activity, and moved the operating lengths of the uniarticular hip flexor and extensor muscles slightly closer to those seen during running. These combined changes in musculotendon kinematics and coordination could potentially contribute to the improved running performances that have been previously observed immediately after cycling on atriathlon-specific bicycle.