Kinetic Properties and Emg Activity of Normal and Over-Speed Pedaling in Track Sprint Cyclists: A Case Study (original) (raw)
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Mechanical Effectiveness and Coordination: New Insights into Sprint Cycling Performance
Biomechanics of Training and Testing, 2018
The pedaling task remains a multijoint task with biomechanical constraints (e.g., circular trajectory of the pedal) requiring specific coordination of the lower-limb muscles. This chapter attempts to provide an overview of how aspects related to pedaling technique and muscle coordination partly account for maximal cycling power capability (i.e., sprint exercise). Our aim in this chapter is (i) to define the typical concepts involved, (ii) discuss the practical information provided (with some examples) and (iii) highlight the main messages for optimizing coordination and sprint performance. Provided that the dynamometer used is capable of dissociating the force produced by each leg with sufficient temporal resolution and measuring the orientation of force, it is possible to analyze the pedal force profile throughout the cycle and the capacity of the athlete to effectively orientate this force. Using inverse dynamics (including calculation of both muscular and nonmuscular components) and measuring EMG activity our interpretation can clearly be taken to a new level by better characterizing the involvement of each muscle group. Despite their inherent limitations, these data represent useful information about the force-generating capacity of big muscle groups (extensors and flexors) as well as about pedaling technique, especially for exercise performed at low and intermediate pedaling rates around which maximal power output is produced. It is possible in practice to identify any potential weakness in the contribution of specific muscle groups (extensor and flexors of the hip, knee and ankle) and finally to characterize muscle coordination and its key role as a limiting factor of maximal power.
Adjustment of Muscle Coordination during an All-Out Sprint Cycling Task
Medicine & Science in Sports & Exercise, 2012
Purpose: This study was designed to assess muscle coordination during a specific all-out sprint cycling task (Sprint). The aim was to estimate the EMG activity level of each muscle group by referring to the submaximal cycling condition (Sub150 W) and to test the hypothesis that a maximal activity is reached for all of the muscles during Sprint. Methods: Fifteen well-trained cyclists were tested during submaximal and sprint cycling exercises and a series of maximal voluntary contractions (MVCs) in isometric and isokinetic modes (MVC at the three lower limb joints). Crank torque and surface EMG signals for 11 lower limb muscles were continuously measured. Results: Results showed that Sprint induced a very large increase of EMG activity level for the hip flexors (multiplied by 7-9 from 150 W to Sprint) and the knee flexors and hip extensors (multiplied by 5-7), whereas plantar flexors and knee extensors demonstrated a lower increase (multiplied by 2-3). During Sprint, EMG activity level failed to reach a maximal value for hamstrings, tibialis anterior, tensor fasciae latae, and gluteus maximus (i.e., G70% to 80% of peak EMG activity during MVC, P G 0.05 to P G 0.001), and individual EMG patterns demonstrated a significant earlier onset and/or later offset for the majority of the muscles (P G 0.01 to P G 0.001). Conclusions: Results clearly suggest a change in the relative contribution of the different muscles to the power production between Sub150 W and Sprint, and provide evidence that EMG activity level is not systematically maximal for all muscles involved in the all-out sprint cycling task. The longer period of activity induced during Sprint is likely to represent an interesting coordination strategy to enhance the work generated by all of the muscle groups. FIGURE 1-The testing conditions and global body posture retained for the MVC efforts on the Con-Trex ergometer. Here shown are the specific examples of isometric MVC for the hip flexion (in 60-hip flexion position (A), the knee flexion (in 50-knee flexion position) (B), and the dorsi flexion (supine with 0-mid ankle position) (C). For the knee and hip angular positions, 0-is when the joints are fully extended.
International Journal of Sports Medicine, 2005
The 200 m flying start is the qualifying race for the "Match Sprint" competition. "Match Sprint" is considered to involve the most explosive effort amongst high-performance track-cycling events. It can be said to include three phases: an acceleration phase (before the start of timed portion of the flying 200 m), a maximal velocity phase, and a deceleration phase (the last both included between the start and finish lines of the 200 m). Outstanding national and international performances are commonly completed within 10 -11 s. This has not been significantly improved over the last twenty years . Also, in contrast with road cycling, the absence of any gear system means that the constant gear ratio chosen before the race directly influences the mean
Comparison of Biomechanical Data of a Sprint Cyclist in the Velodrome and in the Laboratory
ISBS Proceedings Archive, 2018
The aim of this study was to develop a reliable testing method to measure biomechanical variables that describe sprint cycling performance on a velodrome track, compared to on an ergometer in a laboratory. Seven elite track sprint cyclists performed sprints on an isokinetic ergometer in a laboratory and over half lap distances in a velodrome. Key biomechanical variables characterising sprint cycling were measured. Relatively small differences in the variables were found between the ergometer and track sprints. However, the static task constraints of ergometer cycling led the cyclists to adopt a different position which seemed to allow them to increase overall power output and rate of force development. Future research is needed to assess whether the differences in joint angles and crank powers were due to the different environmental and task constraints between the ergometer and the track bicycle sprints.
Maximal muscular power: lessons from sprint cycling
Sports Medicine - Open, 2021
Maximal muscular power production is of fundamental importance to human functional capacity and feats of performance. Here, we present a synthesis of literature pertaining to physiological systems that limit maximal muscular power during cyclic actions characteristic of locomotor behaviours, and how they adapt to training. Maximal, cyclic muscular power is known to be the main determinant of sprint cycling performance, and therefore we present this synthesis in the context of sprint cycling. Cyclical power is interactively constrained by force-velocity properties (i.e. maximum force and maximum shortening velocity), activation-relaxation kinetics and muscle coordination across the continuum of cycle frequencies, with the relative influence of each factor being frequency dependent. Muscle cross-sectional area and fibre composition appear to be the most prominent properties influencing maximal muscular power and the power-frequency relationship. Due to the role of muscle fibre composi...
European Journal of Applied Physiology, 2007
Performance models provide an opportunity to examine cycling in a broad parameter space. Variables used to drive such models have traditionally been measured in the laboratory. The assumption, however, that maximal laboratory power is similar to field power has received limited attention. The purpose of the study was to compare the maximal torque-and power-pedaling rate relationships during ''all-out'' sprints performed on laboratory ergometers and on moving bicycles with elite cyclists. Over a 3day period, seven male (mean ± SD; 180.0 ± 3.0 cm; 86.2 ± 6.1 kg) elite track cyclists completed two maximal 6 s cycle ergometer trials and two 65 m sprints on a moving bicycle; calibrated SRM powermeters were used and data were analyzed per revolution to establish torque-and power-pedaling rate relationships, maximum power, maximum torque and maximum pedaling rate. The inertial load of our laboratory test was (37.16 ± 0.37 kg m 2), approximately half as large as the field trials (69.7 ± 3.8 kg m 2). There were no statistically significant differences between laboratory and field maximum power (1791 ± 169; 1792 ± 156 W; P = 0.863), optimal pedaling rate (128 ± 7; 129 ± 9 rpm; P = 0.863), torque-pedaling rate linear regression slope (-1.040 ± 0.09;-1.035 ± 0.10; P = 0.891) and maximum torque (266 ± 20; 266 ± 13 Nm; P = 0.840), respectively. Similar torque-and powerpedaling rate relationships were demonstrated in laboratory and field settings. The findings suggest that maximal laboratory data may provide an accurate means of modeling cycling performance.
Muscle Stiffness and Rate of Torque Development during Sprint Cycling
Medicine & Science in Sports & Exercise, 2009
WATSFORD, M., M. DITROILO, E. FERNÁ NDEZ-PEÑ A, G. D'AMEN, and F. LUCERTINI. Muscle Stiffness and Rate of Torque Development during Sprint Cycling. Med. Sci. Sports Exerc., Vol. 42, No. 7, pp. 1324-1332, 2010. Purpose: Crank torque (CT) application and rate of CT development (RCTD) are important considerations in sprint cycling. The stiffness of the musculotendinous unit is related to the isometric rate of torque development (RTD); however, this relationship has yet to be examined in sprint cycling. Methods: Maximal isometric torque (MIT) and isometric RTD of the quadriceps were assessed in 21 trained male cyclists (28.7 T 9.5 yr, 1.74 T 0.08 m, and 67.5 T 7.2 kg). Unilateral musculoarticular (MA) stiffness of the quadriceps was quantified using an oscillation test. Further, the participants performed a maximal 6-s sprint to assess peak power output (PO peak ), peak CT (CT peak ), peak RCTD (RCTD peak ), and the crank angles associated with CT peak and RCTD peak . Participants were ranked on MA stiffness properties and were divided into a relatively stiff group (SG) and a relatively compliant group (CG). Results: The SG displayed a significantly higher MA stiffness than the CG (P G 0.05). Furthermore, the SG reported significantly elevated MIT (27%), RTD (26%), and RCTD peak (16%) when compared with the CG (P G 0.05), along with trends for increased PO peak (7%) and CT peak (8%). The angles at CT peak and RCTD peak were 7% and 12% lower for the SG, respectively (P G 0.05). MA stiffness was significantly correlated with RCTD peak , MIT, RTD, and PO peak . Conclusions: Higher stiffness is related to superior RCTD peak in trained cyclists during a single sprint. A significant proportion of the variance in RCTD peak was attributed to MA stiffness (37%), which was of greater magnitude than the relationship between RCTD peak and MIT. Furthermore, the lower CT peak angle and RCTD peak angle may contribute to a more rapid development of CT. Accordingly, MA stiffness seems to be an important consideration for sprint cycling.
Force-Velocity Profiles of Elite Athletes Tested on a Cycle Ergometer
Montenegrin Journal of Sports Science and Medicine, 2018
The present study explored the sensitivity of the force-velocity (F-V) modelling approach obtained from maximal sprints on a leg cycle ergometer to detect selective changes of the mechanical capacities of the lower body muscles associated with high-level training. Specifically, we assumed that the F-V relationship parameters, such as maximum force (F 0), velocity (V 0), power (P M) and slope, would differ among individuals of different high-level training backgrounds. In total, 111 elite athletes divided into four groups (Combat sports, Athletic sprints, Team sports and Physically active) performed maximal sprints on a leg cycle ergometer loaded with 7%, 9%, and 11% of body weight. The findings obtained suggest an exceptionably strong and linear F-V relationship in most of the participants (r > 0.95), while higher P M have been found in all groups of athletes compared to the Physically active group (p < 0.05). In addition, sport-specific F-V profiles have been observed in athletes that belong to distinctively different sports (i.e. higher F 0 and forceoriented slope for strength-trained Combat sports and higher V 0 for speed-trained Athletic sprints). To our knowledge, this is one of the rare studies that evaluate the F-V profiles with such a large sample of elite athletes obtained from commonly used task such as maximal sprints on a leg cycle ergometer. The results obtained support a high sensitivity of the F-V modelling approach to distinguish among elite athletes with different training histories. KEY WORDS sprint cycling test, force-velocity relationship, sensitivity, linear regression, elite athletes A more promising solution of the discussed problem could be based on recent research focused upon the modelling of the F-V relationship of muscular system with performing different functional tasks or sport activities under two or more loading conditions. Specifically, the loaded functional multi-joint movements (e.g.
Leg muscle recruitment in highly trained cyclists
Journal of Sports Sciences, 2006
In this study, we examined patterns of leg muscle recruitment and coactivation, and the relationship between muscle recruitment and cadence, in highly trained cyclists. Electromyographic (EMG) activity of the tibialis anterior, tibialis posterior, peroneus longus, gastrocnemius lateralis and soleus was recorded using intramuscular electrodes, at individual preferred cadence, 57.5, 77.5 and 92.5 rev x [min.sup.-1]. The influence of electrode type and location on recorded EMG was also investigated using surface and dual intramuscular recordings. Muscle recruitment patterns varied from those previously reported, but there was little variation in muscle recruitment between these highly trained cyclists. The tibialis posterior, peroneus longus and soleus were recruited in a single, short burst of activity during the downstroke. The tibialis anterior and gastrocnemius lateralis were recruited in a biphasic and alternating manner. Contrary to existing hypotheses, our results indicate litre co-activation between the tibialis posterior and peroneus longus. Peak EMG amplitude increased linearly with cadence and did not decrease at individual preferred cadence. There was litre variation in patterns of muscle recruitment or co-activation with changes in cadence. Intramuscular electrode location had litre influence on recorded EMG. There were significant differences between surface and intramuscular recordings from the tibialis anterior and gastrocnemius lateralis, which may explain differences between our findings and those of previous studies.