Amplitude and timing of electromyographic activity during sprinting

Abstract

Amplitude and timing of electromyographic activity during sprinting. Scand J Med Sci Sports 1996: 6: 15-21. 0 Munksgaard, 1996 The aim of this study was to make descriptive analyses of the muscle activities in the lower extremity during maximal sprinting. Nine healthy sprinters were examined during maximal sprinting using telemetric electromyography (EMG). Seven muscles of the lower extremities were investigated: biceps femoris, medial hamstrings (semimembranosus and semitendinosus), rectus femoris, gluteus maximus, tibialis anterior, lateral gastrocnemius and medial gastrocnemius. The recorded EMG levels during running were expressed as percentage of maximum voluntary isometric contractions ('%omax EMG). For each muscle, the normalized EMG was plotted during the whole running stride cycle and is presented for each muscle. The reason for using this method is to show that it is possible to compare different muscle activities in a runner as well as to make comparisons between runners. Lateral and medial hamstrings and gluteus maximus showed similar activities with peak levels of EMG during footstrike. Rectus femoris had a two-peak activity, with one peak at the middle of the stance phase and the other during the swing phase. The tibialis anterior also showed a two-peak activity, but with the peaks at the beginning of the swing phase and just before foot-strike. The highest activities of the medial and lateral gastrocnemius occurred just before toe-off.The activation of different muscles in the lower extremities in sprinting as shown in recordings of temporal distribution of raw electromyographic (EMG) activity has been studied by several researchers. Maim et al. made a comparative study of the lower extremity in jogging, running and sprinting. The EMG activity was not graded, it only registered activity or not during different parts of the stride cycle (1). In another study Mann and Hagy concluded that increased speed was followed by increased E M G activity in a temporal aspect; however, the activity was not graded (2). Simonsen et al. (3) studied the temporal distribution of EMG from 9 muscles during sprinting together with mechanical analyses. Movement artifacts made it difficult to grade the EMG activity in this study. Mero & Komi used a telemetric device to record activity of elite sprinters during maximal sprinting. The EMG was normalized to maximal integrated EMG during the running stride cycle and the activity was measured ten times during one stride cycle (4). Jacobs et al. (5) studied the activity of the lower legs by integrated EMG in 7 elite runners by telemetric transmission. The recorded EMG levels during running were expressed as a percentage of maximum voluntary isometric contractions. However, the running speed was only 6 m/s. Jacobs et al. (6) also used EMG normalized to maximum isometric contractions in the lower extremities to study the activity in a sprint push-off. This is at the very beginning in the sprint run at the acceleration phase.In comparing fatigued and nonfatigued sprinting, Nummela...

The human gluteus maximus and its role in running

“…As suggested (McLay et al, 1990), the most likely function of swing-side contractions of the GM is to decelerate the leg during swing phase. These results are also consistent with those reported by previous studies (Mann and Hagy, 1980b; Montgomery et al, 1984;Nilsson et al, 1985;Jonhagen et al, 1996). While this hypothesis is difficult to test, it is consistent with data on both the timing and magnitude of normalized GM contractions at different speeds.…”

“…One of these functions may be to help actively extend the thigh during stance (Hypothesis 4). In particular, the timing and magnitude of stance-side GM contractions were very similar to those of the hamstrings during both walking and running, confirming the results of several previous studies (Mann and Hagy, 1980b;Montgomery et al, 1984;Nilsson et al, 1985;Jonhagen et al, 1996). Such results are particularly interesting in terms of uphill locomotion.…”

“…The GM was reported to be active at strong to moderate levels at the end of swing phase and during the first third of stance during running (Mann and Hagy, 1980a;Mann and Hagy, 1980b;Montgomery et al, 1984;Nilsson et al, 1985). In addition, it has been reported that GM activity during running peaks near the time of footstrike, and has a similar pattern of contract to the hamstrings (Jonhagen et al, 1996). Unfortunately, only one study has directly compared GM activity in walking and running (Stern et al, 1980), and only in a general qualitative way in one subject.…”

Strengthening and Neuromuscular Reeducation of the Gluteus Maximus in a Triathlete with Exercise-Associated Cramping of the Hamstrings

“…11,27 In this case report, preintervention EMG recordings of the hamstrings during terminal swing and the first half of the stance phase of running revealed average levels of hamstring activity (48.1% MVIC), well above what is considered normal for running. Based on EMG recordings, Pinnington et al 25 reported the average hamstring activity during terminal swing and the first half of the stance phase of running to be 19% MVIC.…”

Evaluation and Imaging of an Untreated Grade III Hamstring Tear: A Case Report

“…Submaximal contractions are used in everyday life, but high-force eccentric (lengthening) contractions, such as in the hamstring muscles during sprinting, are associated with muscle damage and pain [18,27,37]. The majority of hamstring musculotendinous injuries occur during maximum sprinting when braking knee extension or at foot strike [7], whereas most proximal hamstring avulsions occur during forced hip flexion and knee extension, such as with a fall during waterskiing [9,20]. In one kinematic and electromyographic study late swing phase Each author certifies that he or she has no commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article.…”