Muscle activation sequencing of leg muscles during linear glide shot putting

Abstract

In the shot put, the athlete's muscles are responsible for generating the impulses to move the athlete and project the shot into the air. Information on phasic muscle activity is lacking for the glide shot put event and therefore important technical information for coaches is not currently available. This study provides an electromyography (EMG) analysis of the muscle activity of the legs during shot put. Fifteen right-handed Irish national level shot putters performed six maximum effort throws using the glide shot put technique. EMG records of eight bilateral lower limb muscles (rectus femoris, biceps femoris, medial- and lateral-gastrocnemius) were obtained during trials. Analysis using smooth EMG linear envelopes revealed patterns of muscle activity across the phases of the throw and compare men and women performers. The results showed that the preferred leg rectus femoris, the preferred leg biceps femoris and the non-preferred leg biceps femoris play important roles in the glide technique, with the total duration of high volumes of activity between 34 and 53% of the throw cycle. A comprehensive understanding of movement and muscle activation patterns for coaches could be helpful to facilitate optimal technique throughout each of the key phases of the event.

Muscle Force Patterns in Lower Extremity Muscles for Elite Discus Throwers, Javelin Throwers and Shot-Putters – A Case Study

“…Terzis et al (2007) presented no significant correlation between gastrocnemius muscle activity and shot put performance, yet still it is possible that such a correlation could be found for the soleus muscle in future research. Nevertheless, an interesting finding is that Howard et al (2017) observed high activity in the left leg gastrocnemius in their research, something which was not found in the present study. Some speculation can be offered as to the reasons for this inconsistency.…”

“…However, in the current study, at the beginning of the delivery phase the right knee extensors, to which the rectus femoris belongs, generated the highest forces; yet the right knee flexors were not among the muscles that generated the highest forces. Even though Howard et al (2017) indicate that the rectus femoris of the left leg is only active during the transition stage of the shot put, these results suggest that despite its short activation time, it is crucial for a successful throw. Considering all the athletes, the left knee extensors generated the highest forces in sub-phase II.…”

“…One way to validate the results of musculoskeletal simulation is by comparing the estimated muscle activity with electromyography. Howard et al (2017) recorded biopotentials from the rectus femoris, biceps femoris, as well as the medial and lateral gastrocnemius muscles during the shot put. Those authors presented a map of the muscle activation in relation to what percentage of the cycle had occurred.…”

“…To obtain information about muscle activity, electromyography (EMG) is used. Howard et al (2017) present a map of electrical activation in chosen muscles of the lower extremities for shot putters. Those authors suggest that the conducted research will provide coaches with new information concerning throwing techniques.…”

Impact of antagonistic muscle co-contraction on in vivo knee contact forces

“…For a comparison between the resulting EMG envelopes and the muscle forces predicted by COC -model, the signal of each muscle group in both data sets was normalized to its maximum during all stance phases of the same patient and activity [ 36 ]. The activation state of the muscle groups was identified from the normalized data using a 50% threshold of the maximal value [ 37 ]. The temporal agreement was quantified as the fraction of the time during which the on/off state was consistent between EMG and the model.…”