Electromechanical delay estimated by using electromyography during cycling at different pedaling frequencies

Li, Li; Baum, Brian S.

doi:10.1016/j.jelekin.2004.04.004

Cited by 50 publications

(48 citation statements)

References 27 publications

(46 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Neptune et al (1997) found that six of the eight muscles they investigated displayed neuromuscular activity shifting earlier in the crank cycle with increased cadence. Baum and Li (2003), Bieuzen et al (2007), Li and Baum (2004), and Lepers (2005, 2007) have all corroborated their results. The activation dynamics hypothesis is not undisputed, though.…”

Section: Introductionmentioning

confidence: 55%

“…Neptune et al (1997) aptly named the idea the activation dynamics hypothesis. EMD can be defined as the time between neuromuscular activation, the electrical outcome, and force, the mechanical outcome (Li and Baum, 2004;Sarre and Lepers, 2005), and is regarded as being fairly constant (Li and Baum, 2004;Sarre and Lepers, 2007). Ingen Schenau et al (1995) found EMD to approximate 90 ms in most of the leg muscles during cycling, as did Vos et al (1991).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The effect of cadence on timing of muscle activation and mechanical output in cycling: On the activation dynamics hypothesis

McGhie

Ettema

2011

Journal of Electromyography and Kinesiology

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 55%

Section: Introductionmentioning

confidence: 99%

The effect of cadence on timing of muscle activation and mechanical output in cycling: On the activation dynamics hypothesis

McGhie

Ettema

2011

Journal of Electromyography and Kinesiology

View full text Add to dashboard Cite

“…It has been reported that isometric knee-extension training at 70% of maximal voluntary contraction reduced electromechanical delay by 18%. 14 If the electromechanical delay is, for example, 100 milliseconds, 15,16 it corresponds to 57° of crank revolution during post 57 ± 6 -7 ± 2 138 ± 26 53 ± 6 -12 ± 2 158 ± 6 73 ± 5 -7 ± 3 101 ± 22…”

Section: Discussionmentioning

confidence: 99%

Cyclists’ Improvement of Pedaling Efficacy and Performance After Heavy Strength Training

Hansen¹,

Rønnestad²,

Vegge³

et al. 2012

International Journal of Sports Physiology and Performance

View full text Add to dashboard Cite

The authors tested whether heavy strength training, including hip-flexion exercise, would reduce the extent of the phase in the crank revolution where negative or retarding crank torque occurs. Negative torque normally occurs in the upstroke phase when the leg is lifted by flexing the hip. Eighteen well-trained cyclists either performed 12 wk of heavy strength training in addition to their usual endurance training (E+S; n = 10) or merely continued their usual endurance training during the intervention period (E; n = 8). The strength training consisted of 4 lower body exercises (3 × 4-10 repetition maximum) performed twice a week. E+S enhanced cycling performance by 7%, which was more than in E (P = .02). Performance was determined as average power output in a 5-min all-out trial performed subsequent to 185 min of submaximal cycling. The performance enhancement, which has been reported previously, was here shown to be accompanied by improved pedaling efficacy during the all-out cycling. Thus, E+S shortened the phase where negative crank torque occurs by ~16°, corresponding to ~14%, which was more than in E (P = .002). In conclusion, adding heavy strength training to usual endurance training in well-trained cyclists improves pedaling efficacy during 5-min all-out cycling performed after 185 min of cycling.

show abstract

“…Notably, the increase in power output in these studies and in the present work was partially due to an increase in movement velocity (i.e., cadence or stroke frequency). Assuming a constant electromechanical delay of about 100 ms (Cavanagh and Komi 1979), it would be expected that muscle activation occurs progressively earlier as movement velocity increases in order to develop force in the same part of the cycle (Li and Baum 2004). For instance, an electromechanical delay of 100 ms corresponds to 9% of the drive phase at P60 (about 27 strokes min -1 ) and 11% of the drive phase at P120 (about 32 strokes min -1 ).…”

Section: Discussionmentioning

confidence: 99%

Effect of power output on muscle coordination during rowing

et al. 2011

View full text Add to dashboard Cite

The present study was designed to quantify the effect of power output on muscle coordination during rowing. Surface electromyographic (EMG) activity of 23 muscles and mechanical variables were recorded in eight untrained subjects and seven experienced rowers. Each subject was asked to perform three 2-min constant-load exercises performed at 60, 90 and 120% of the mean power output over a maximal 2,000-m event (denoted as P60, P90, and P120, respectively). A decomposition algorithm (nonnegative matrix factorization) was used to extract the muscle synergies that represent the global temporal and spatial organization of the motor output. The results showed a main effect of power output for 22 of 23 muscles (p values ranged from <0.0001 to 0.004) indicating a significant increase in EMG activity level with power output for both untrained and experienced subjects. However, for the two populations, no dramatic modification in the shape of individual EMG patterns (mean r (max) value = 0.93 ± 0.09) or in their timing of activation (maximum lag time = -4.3 ± 3.8% of the rowing cycle) was found. The results also showed a large consistency of the three extracted muscle synergies, for both synergy activation coefficients (mean r (max) values range from 0.87 to 0.97) and muscle synergy vectors (mean r values range from 0.70 to 0.76) across the three power outputs. In conclusion, despite significant changes in the level of muscle activity, the global temporal and spatial organization of the motor output is very little affected by power output on a rowing ergometer.

show abstract

Electromechanical delay estimated by using electromyography during cycling at different pedaling frequencies

Cited by 50 publications

References 27 publications

The effect of cadence on timing of muscle activation and mechanical output in cycling: On the activation dynamics hypothesis

The effect of cadence on timing of muscle activation and mechanical output in cycling: On the activation dynamics hypothesis

Cyclists’ Improvement of Pedaling Efficacy and Performance After Heavy Strength Training

Effect of power output on muscle coordination during rowing

Contact Info

Product

Resources

About