Cadence, power, and muscle activation in cycle ergometry

Abstract

. Purpose: Based on the resistance-rpm relationship for cycling, which is not unlike the force-velocity relationship of muscle, it is hypothesized that the cadence which requires the minimal muscle activation will be progressively higher as power output increases. Methods: To test this hypothesis, subjects were instrumented with surface electrodes placed over seven muscles that were considered to be important during cycling. Measurements were made while subjects cycled at 100, 200, 300, and 400 W at each cadence: 50, 60, 80, 100, and 120 rpm. These power outputs represented effort which was up to 32% of peak power output for these subjects. Results: When all seven muscles were averaged together, there was a proportional increase in EMG amplitude each cadence as power increased. A second-order polynomial equation fit the EMG:cadence results very well (r 2 ϭ 0.87-0.996) for each power output. Optimal cadence (cadence with lowest amplitude of EMG for a given power output) increased with increases in power output: 57 Ϯ 3.1, 70 Ϯ 3.7, 86 Ϯ 7.6, and 99 Ϯ 4.0 rpm for 100, 200, 300, and 400 W, respectively. Conclusion: The results confirm that the level of muscle activation varies with cadence at a given power output. The minimum EMG amplitude occurs at a progressively higher cadence as power output increases. These results have implications for the sense of effort and preferential use of higher cadences as power output is increased.

Muscle coordination limits efficiency and power output of human limb movement under a wide range of mechanical demands

“…The participants completed a 10-min warm-up at a freely chosen cadence, with 5 min at 100 W followed by 5 min increasing 20 W each minute. The conditions were first randomized by cadence, and then each power output was presented in random order to help ensure compliance of the desired cadence (MacIntosh et al 2000). The geometry of the cycle trainer was matched to each participant's own bicycle as closely as possible, and they used their own clipless pedals and shoes.…”

“…Also, to evaluate the presence of fatigue additional 30-s trials were completed, at the same cadence as the first trial at 200 W, prior to the 1st and 17th trials and after the last trial (MacIntosh et al 2000), where an increase in EMG intensity was expected where fatigue was present (Edwards and Lippold 1956;Housh et al 2000;Petrofsky 1979;Sarre and Lepers 2005).…”

“…First, the relative excitation of each muscle is both workload Wakeling 2012, 2013;Ericson 1986;Ericson et al 1985;Hug et al 2004;Jorge and Hull 1986;Sarre et al 2003;Wakeling et al 2010;Wakeling and Horn 2009) and cadence dependent, with many discrepancies in the collective research (Ericson 1986;Ericson et al 1985;Lucia et al 2004;Neptune et al 1997;Sarre et al 2003;Lepers 2005, 2007;Takaishi et al 1996Takaishi et al , 1998Wakeling et al 2006;Wakeling and Horn 2009). Evidence suggests that individual muscles exhibit workloaddependent relationships between muscle excitation and cadence (MacIntosh et al 2000), which may explain the discrepancies as a wide range of workloads were employed. The timing of muscle excitation has also been shown to be affected by cadence, with several muscles exhibiting a phase advance and/or larger duty cycle with increasing cadence (Baum and Li 2003;Dorel et al 2012;Marsh and Martin 1995;Neptune et al 1997;Samozino et al 2007;Lepers 2005, 2007;Wakeling and Horn 2009), and both influenced (Sarre and Lepers 2007) and not influenced (Jorge and Hull 1986) by workload, but relatively little research has been completed in this area.…”

“…This partially explains evidence that efficiency is maximized at increasing cadences for increasing power outputs (Böning et al 1984;Coast and Welch 1985;Foss and Hallén 2004;Hagberg et al 1981;Seabury et al 1977). Obtaining greater efficiency by increasing cadence with workload may be the result of reduced muscle excitation since minimum muscle excitation also occurs at increasing cadences with increasing submaximal workloads (MacIntosh et al 2000), despite different muscle excitationworkload-cadence relationships seen in individual muscles (Blake and Wakeling 2013;Hug et al 2004;Lawrence and De Luca 1983;MacIntosh et al 2000).…”

Implicações da cadência de pedalada sobre a potência mecânica e o período de contração muscular no ciclismo

“…Porém, até o momento não se tem conhecimento de como variações na cadência de pedalada podem in uenciar o tipo de ação muscular utilizada. A menor atividade muscular para uma determinada carga de trabalho ocorre em uma cadência especí ca 6 , e, portanto, variações na cadência de pedalada com a manutenção da carga de trabalho podem resultar em alteração da mecânica muscular e/ou articular em função de alterações na atividade muscular. Estudos prévios observaram redução no trabalho mecânico do joelho associado à redução na amplitude de movimento das articulações do joelho e do tornozelo em ciclistas pedalando em cadências elevadas (> 90 rpm) [7][8] .…”