Biomechanical Comparison Between Sprint Start, Sled Pulling, and Selected Squat-Type Exercises

Abstract

Okkonen, Olli 2012. Biomechanical comparison between sprint start, sled-pulling and selected squat type exercises. Department of Biology of Physical Activity, University of Jyväskylä.Master's Thesis in Science of Sport Coaching and Fitness Testing. 69 pp.The purpose of the present study was to compare kinetics, kinematics and muscle activity between sprint start, sled-pulling and selected squat type exercises and also to examine how different exercises and variables correlate with the performance time of the block start (10 m).Nine male athletes (4 sprinters, 3 decathlonists, 1 long jumper and 1 triple jumper; mean ± SD; age = 24.9 ± 3.9 yr; height = 180.4 ± 5.9 cm; weight = 80.3 ± 7.5 kg; 100 m record = 11.35 ± 0.29 s) performed measurements and different force-time, electromyographic (EMG) and kinematic variables were compared to sprint start. Most of the comparison was done to the block phase (the phase of force production towards starting blocks) of the block start. In nearly all exercises, the activity of the gluteus maximus (GM) was significantly (p≤0.05) higher than during the block phase. The opposite was true for the activation of the biceps femoris (BF).Ground reaction forces (GRF) were highest during the 1-RM (one repetition maximum) ½-squat (SMAX). The GRFs were also significantly (p≤0.05) larger during the countermovement jumps (CMJ) with different loads and during the ½-squat with 70 % of 1-RM (S70) as compared to the block phase. The angular velocity of the knee was significantly (p≤0.05) higher during CMJs than during the block phase. The highest correlation existed between the performance time in the block start (10 m) and the takeoff velocity during CMJ (r=-0.950, p≤0.05). According to the results of the present study, it can be suggested that to overload the force production (peak and average force) of the block phase, CMJs and ½-squats could be used in training. If the aim is to activate the GM intensively, almost all of the exercises analyzed in the present study seems to be suitable. The results also indicate that CMJs could be used as supra-velocity exercise for the knee joint in the training of the block start. In addition, the correlation analyses indicate the importance of a good performance in CMJs for a good performance in the block start.

Effects of Sled Towing on Peak Force, the Rate of Force Development and Sprint Performance During the Acceleration Phase

“… Maulder et al (2008) also agreed that a load of approximately 10% Bm may not provide a sufficient training stimulus in a block start action. The use of higher loads for sled towing may provide training stimulus for young athletes, when also considering the increase in muscular activity in sled towing ( Okkonen and Häkkinen, 2013 ). Cormie et al (2011b) suggested the use of an optimal load would provide an effective stimulus to elicit increases in maximal power output.…”

“…Ideally, athletes using sled towing should imitate the range of motion, body position, muscle activation time, and sprint velocity near the running speeds used in competition ( Alcaraz et al, 2009 ; Kanehisa and Miyashita, 1983 ; Kaneko et al, 1983 ; Murray et al, 2005 ). Furthermore, Okkonen and Häkkinen (2013) found that resisted sprint exercises produce greater muscular activation when compared to free sprinting. Additionally, this training method increases force output ( Alcaraz et al, 2014 ; Harrison and Bourke, 2008), stride length in the acceleration phase in team sport athletes ( Kawamori et al, 2014a ), the maximum velocity phase in sprinters ( Alcaraz et al, 2014 ), and stride frequency in the acceleration and maximum speed phase ( Clark et al, 2010 ; Zafeiridis et al, 2005 ).…”

Effect of a Wide Stance on Block Start Performance in Sprint Running

“…These findings suggest that the hip extensor kinetics is a key contributor to high block-induced power. This leg extension motion during the block start phase is similar to the double-legged squat motion [ 10 ]. Biomechanical analysis of the squatting motion has revealed that lengthening the mediolateral distance between feet (140% of shoulder width) contributes to stronger isometric contractions in lower limb muscles [ 11 ].…”

Lower limb muscle activation and kinematics modifications of young healthy adults while pushing a variable resistance sled

“…Therefore, the recommended intervention for targeting a weak quad muscle would be the WP task, because it is the most beneficial activity for training both strength and endurance due to the increased muscle activation as well as the later timing in maximal contraction. Studies showed (Maddigan M, Button D, Behm D., 2014& Okkonen, O. & Häkkinen, K. 2013) similar activation of the Quads muscle pushing a sled compared to a squat manoeuvre and squat type exercises.…”

“…& Häkkinen, K. 2013) similar activation of the Quads muscle pushing a sled compared to a squat manoeuvre and squat type exercises. In addition, it has been found in multiple studies (Okkonen, O. & Häkkinen, K., 2013& Fry, A.C., Smith, J.C., & Schilling, B.K., 2003 that performing a squat without proper form can increase stress at the knee joint.…”