Training With Independent Cranks Alters Muscle Coordination Pattern in Cyclists
UNIVERSITA’ DEGLI STUDI DI URBINO
Fernández-Peña, E, Lucertini, F, and Ditroilo, M.
J Strength Cond Res 23(6): 1764-1772, 2009
In cycling, a circular pedaling action makes the most useful contribution to forward propulsion. Training with independent cranks (IC) has been proposed to improve the pedaling action. The aims of this study were, first, to assess whether the intermuscular coordination pattern of the pedaling action with normal cranks (NC) is modified after a training period with IC and, second, to determine if the new coordination pattern is maintained after a washing-out period. Eighteen cyclists, divided into a control (CG) and an experimental (EG) group, underwent 2 test sessions (T1 and T2) separated by 2 weeks of training (18 hours). The electromyographic (EMG) activity of 4 lower limbs' muscles was recorded while the athletes pedaled at 80 rpm for 60 seconds at 30 and 50% of the maximal power output determined during a maximal pedaling test. The tasks were performed with IC (EG) and NC (EG and CG). The EG underwent a retention test session (T3) after another 18-hour training with NC. EG showed a significant (45.8 ± 8.8 vs. 36.0 ± 6.1%, p < 0.01 at 30% intensity) and a quasi-significant (62.7 ± 10.3 vs. 54.2 ± 8.7%, p = 0.09 at 50% intensity) decrease in vastus lateralis EMG activity and a quasi-significant (36.4 ± 13.4 vs. 43.5 ± 10.9%, p = 0.09 at 30% intensity) and a significant (54.5 ± 12.1 vs. 65.5 ± 16.1%, p < 0.05 at 50% intensity) increase in biceps femoris EMG activity between T1-NC and T2-NC. By T3, EMG activity returned to initial levels (T1). On the contrary, CG did not reveal any significant variation. The results provide scientific support for muscle coordination pattern alteration from the use of IC, potentially achieving a more effective pedaling action. IC training reduces quadriceps exertion, thus preserving it for important moments during competition.
This study explains the results of Abbiss, who showed substantial metaboic changes in certain muscles after counterweighted single-legged training. Of course such changes are going to occur if you start using the muscles more. And, the regression does not surprise us as the adaption period was short in this study so one would hardly expect the changes to be permanent. It remains to be seen if one trained for a very long time as to whether the changes can become "permanent" or how slowly they will revert. Find a preliminary slideshow of the study here. Similar changes were seen acutely in a subsequent study by Hug.