Kettlebell swing targets semitendinosus and supine leg curl targets biceps femoris: an EMG study with rehabilitation implications

Abstract

BackgroundThe medial hamstring muscle has the potential to prevent excessive dynamic valgus and external rotation of the knee joint during sports. Thus, specific training targeting the medial hamstring muscle seems important to avoid knee injuries.ObjectiveThe aim was to investigate the medial and lateral hamstring muscle activation balance during 14 selected therapeutic exercises.Study designThe study design involved single-occasion repeated measures in a randomised manner. Sixteen female elite handball and soccer players with a mean (SD) age of 23 (3) years and no previous history of knee injury participated in the present study. Electromyographic (EMG) activity of the lateral (biceps femoris – BF) and medial (semitendinosus – ST) hamstring muscle was measured during selected strengthening and balance/coordination exercises, and normalised to EMG during isometric maximal voluntary contraction (MVC). A two-way analysis of variance was performed using the mixed procedure to determine whether differences existed in normalised EMG between exercises and muscles.ResultsKettlebell swing and Romanian deadlift targeted specifically ST over BF (Δ17–22%, p<0.05) at very high levels of normalised EMG (73–115% of MVC). In contrast, the supine leg curl and hip extension specifically targeted the BF over the ST (Δ 20–23%, p<0.05) at very high levels of normalised EMG (75–87% of MVC).ConclusionSpecific therapeutic exercises targeting the hamstrings can be divided into ST dominant or BF dominant hamstring exercises. Due to distinct functions of the medial and lateral hamstring muscles, this is an important knowledge in respect to prophylactic training and physical therapist practice.

Impact of exercise selection on hamstring muscle activation

“…To some extent, these protective benefits might be mediated by the elongation of BF LongHead fascicles,40 which would be expected to improve the strength of this muscle at long lengths41 and reduce its susceptibility to exercise-induced damage 42. High levels of BF nEMG during the Nordic are consistent with previous investigations,25 and are the result of the supramaximal intensity of the exercise, which potentially explains why high levels of BF nEMG were also observed in the eccentric glute-ham raise. High levels of BF nEMG in concentric actions were observed in several other exercises including the straight-knee bridge, leg curl and the 45° hip extension which corroborates previous observations 25.…”

“…Eighteen athletes (age, 23.9±3.1; height, 180.6±5.9; weight, 86.0±14.8) participated in part 1 and 10 athletes (age, 24.6±4.0; height, 183.5±7.0; weight, 83.5±8.7) participated in part 2. A priori sample size estimates were based on (1) the capacity to detect a 10% difference in the ratio of BF to MH (BF/MH) sEMG amplitude between exercises25 and (2) an effect size of 1.0 in the percentage change in T2 relaxation time between muscles,11 at a power of 0.80 and with p<0.05. Participants were free from soft tissue and orthopaedic injuries to the trunk, hips and lower limbs at the time of testing, and had no known history of cardiovascular, metabolic or neurological disorders.…”

“…The 10 exercises were chosen based on a review of the scientific literature 23 25 27. They included the bilateral and unilateral stiff-leg deadlift, hip hinge, lunge, unilateral bent and straight knee bridges, leg curl, 45° hip extension, glute-ham raise and the Nordic.…”

The Effect of Kettlebell Swing Load and Cadence on Physiological, Perceptual and Mechanical Variables

“…Unlike dumbbells, kettlebell training tends to comprise ballistic and swing movements where the centre of mass of the kettlebell is extended beyond the hand. Kettlebell training has also been recommended to condition occupation groups including the armed services [2] as well as being an efficacious rehabilitation tool [3,4]. While the use of the kettlebell dates back to circa 1700 s [1], scientific analysis of kettlebell training and individual movements with a kettlebell has only recently gathered momentum.…”

Knieverletzungen im Handball

“…Seit das Problem der hohen Präva-lenz von schweren Knieverletzungen im Handball gegen Ende der 1990er Jahre international bekannt wurde [49,68], haben sich viele Studien mit der Analyse extrinsischer und intrinischer Risikofaktoren beschäf-tigt [4,5,13,23,28,[46][47][48]51,53,54,58,59,71,[84][85][86][87][88] (Tab. 1; Abb.…”