Muscular activity level during pedalling is not affected by crank inertial load

Abstract

The aim of the present study was to investigate the influence of gear ratio (GR) and thus crank inertial load (CIL), on the activity levels of lower limb muscles. Twelve competitive cyclists performed three randomised trials with their own bicycle equipped with a SRM crankset and mounted on an Axiom ergometer. The power output ( approximately 80% of maximal aerobic power) and the pedalling cadence were kept constant for each subject across all trials but three different GR (low, medium and high) were indirectly obtained for each trial by altering the electromagnetic brake of the ergometer. The low, medium and high GR (mean +/- SD) resulted in CIL of 44 +/- 3.7, 84 +/- 6.5 and 152 +/- 17.9 kg.m(2), respectively. Muscular activity levels of the gluteus maximus (GM), the vastus medialis (VM), the vastus lateralis (VL), the rectus femoris (RF), the medial hamstrings (MHAM), the gastrocnemius (GAS) and the soleus (SOL) muscles were quantified and analysed by mean root mean square (RMS(mean)). The muscular activity levels of the measured lower limb muscles were not significantly affected when the CIL was increased approximately four fold. This suggests that muscular activity levels measured on different cycling ergometers (with different GR and flywheel inertia) can be compared among each other, as they are not influenced by CIL.

Effects of gradient and speed on freely chosen cadence: The key role of crank inertial load

“…Accordingly, our field data imply that FCC should not be affected per se by W PO , or if there is an influence it is negligible if the indirect effects on v are taken into account. The effect of CIL on some physiological and biomechanical indices has previously been investigated in laboratory-based studies (Duc et al, 2005;Fregly and Zajac, 1996;Hansen et al, 2002b;Lollgen et al, 1975;Patterson et al, 1983;Voigt and von Kiparski, 1989); but results were inconsistent. When a relationship between CIL and the investigated parameter was observed, this tended to occur over very large CIL ranges (90 kg m 2 or over; (Duc et al, 2005;Fregly and Zajac, 1996)), or when comparing laboratory vs. outdoor cycling conditions (Bertucci et al, 2007).…”

“…However, in welltrained cyclists the influence of road gradient (RG) on FCC has not been extensively investigated in order to provide a description of the relationship between these two variables. Among the biomechanical factors potentially affecting FCC, the influence of crank inertial load (CIL), the effect of which counteracts the changes in crank angular speed, was investigated, and results have been controversial (Bertucci et al, 2007;Duc et al, 2005;Fregly and Zajac, 1996;Hansen et al, 2002a, b;Lollgen et al, 1975;Mognoni and di Prampero, 2003;Patterson et al, 1983;Voigt and von Kiparski, 1989). Hansen et al (2002b) studied nine healthy males riding on a treadmill and observed that in some situations CIL can influence FCC to the same extent as power output.…”

Influence of crank length and crank width on maximal hand cycling power and cadence

“…In our study IR was chosen according to reach maximum power after approximately 2-3 s and not with respect to the conditions a handbiker experience using a handbike. However, in cycling, crank inertial load has little eVect on pedalling coordination (Fregly et al 1996) and do not aVect muscular activity level (Duc et al 2005). Therefore, we assume that our ergometer results can be transferred to handbiking even though the inertial load conditions diVer.…”

Isokinetic Cycling and Elliptical Stepping: A Kinematic and Muscle Activation Analysis

“…Other factors that may have affected leg muscle activation and coordination during cycling were the crank inertial load alteration and gear ratio [17], postural effects on biarticular and monoarticular muscles [18], and subject training background [19]. All these factors were not deemed relevant in the current study, as the load and gear ratio were constant, posture was carefully controlled, and subjects were introduced to both exercise systems only during the experimental session.…”