Influence of Squatting Depth on Jumping Performance

Hartmann, Hagen; Wirth, Klaus; Klusemann, Markus J.; Dalic, Josip; Matuschek, Claus; Schmidtbleicher, Dietmar

doi:10.1519/jsc.0b013e31824ede62

Cited by 94 publications

(122 citation statements)

References 90 publications

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“…The increases in maximum strength during this investigation period are likely, primarily, due to neural adaptations, as for example enhanced motor unit activation, reduced neural inhibition, motor unit synchronization, and rate coding which were a result from changes at the central nervous level (1,3,26,35,40,49,50,53,56,60,64). Because of the dynamic training, it is likely that the neural adaptations could not be retrieved under isometric testing conditions (30,69). Hence, it is generally a problem if training exercise and test condition do not match.…”

Section: Discussionmentioning

confidence: 98%

“…However, it was surprising that changes in jump performance in the LP group were so low that the level of significance was not reached, although the improvement of the dynamic maximum strength was high. Still, it can be assumed that at least part of the adaptations in this training exercise transferred to increase performance in SJ and CMJ (30,69) as strong correlations for both dynamic maximal strength tests with the SJ and CMJ (r = 0.665-0.696) were calculated.…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, it also depends on muscle cross-sectional area, fiber type composition, and the discharge rate of the innervating motoneurones (20,49). Strength training-induced increases in speed strength seem indisputable (5,7,14,15,29,30). Several longitudinal investigations found increases in squat jump (SJ) and countermovement jump (CMJ) performance after strength training interventions using different exercises (5,7,14,15,19,24,31,33,42).…”

Section: Introductionmentioning

confidence: 99%

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The Impact of Back Squat and Leg-Press Exercises on Maximal Strength and Speed-Strength Parameters

Wirth

Hartmann

Sander³

et al. 2016

Journal of Strength and Conditioning Research

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Strength training-induced increases in speed strength seem indisputable. For trainers and athletes, the most efficient exercise selection in the phase of preparation is of interest. Therefore, this study determined how the selection of training exercise influences the development of speed strength and maximal strength during an 8-week training intervention. Seventy-eight students participated in this study (39 in the training group and 39 as controls). Both groups were divided into 2 subgroups. The first training group (squat training group [SQ]) completed an 8-week strength training protocol using the parallel squat. The second training group (leg-press training group [LP]) used the same training protocol using the leg press (45° leg press). The control group was divided in 2 subgroups as controls for the SQ or the LP. Two-factorial analyses of variance were performed using a repeated measures model for all group comparisons and comparisons between pretest and posttest results. The SQ exhibited a statistically significant (p ≤ 0.05) increase in jump performance in squat jump (SJ, 12.4%) and countermovement jump (CMJ, 12.0%). Whereas, the changes in the LP did not reach statistical significance and amounted to improvements in SJ of 3.5% and CMJ 0.5%. The differences between groups were statistically significant (p ≤ 0.05). There are also indications that the squat exercise is more effective to increase drop jump performance. Therefore, the squat exercise increased the performance in SJ, CMJ, and reactive strength index more effectively compared with the leg-press in a short-term intervention. Consequently, if the strength training aims at improving jump performance, the squat should be preferred because of the better transfer effects.

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Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Impact of Back Squat and Leg-Press Exercises on Maximal Strength and Speed-Strength Parameters

Wirth

Hartmann

Sander³

et al. 2016

Journal of Strength and Conditioning Research

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“…During the stance, their feet were shoulder width apart and their toes pointed forward or slightly outward. According to the procedure suggested by Hartmann et al [25] the subjects performed the jump by bending the knees to a position they felt comfortable (i.e., preferred starting push-off position). A rest interval of 90 seconds was interspersed between jump repetitions, while 5 minutes was allowed between jump trials.…”

Section: Methodsmentioning

confidence: 99%

Measurement errors when estimating the vertical jump height with flight time using photocell devices: the example of Optojump

Attia¹,

Dhahbi²,

Chaouachi³

et al. 2017

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Common methods to estimate vertical jump height (VJH) are based on the measurements of flight time (FT) or vertical reaction force. This study aimed to assess the measurement errors when estimating the VJH with flight time using photocell devices in comparison with the gold standard jump height measured by a force plate (FP). The second purpose was to determine the intrinsic reliability of the Optojump photoelectric cells in estimating VJH. For this aim, 20 subjects (age: 22.50±1.24 years) performed maximal vertical jumps in three modalities in randomized order: the squat jump (SJ), counter-movement jump (CMJ), and CMJ with arm swing (CMJarm). Each trial was simultaneously recorded by the FP and Optojump devices. High intra-class correlation coefficients (ICCs) for validity (0.98-0.99) and low limits of agreement (less than 1.4 cm) were found; even a systematic difference in jump height was consistently observed between FT and double integration of force methods (-31% to -27%; p<0.001) and a large effect size (Cohen’s d>1.2). Intra-session reliability of Optojump was excellent, with ICCs ranging from 0.98 to 0.99, low coefficients of variation (3.98%), and low standard errors of measurement (0.8 cm). It was concluded that there was a high correlation between the two methods to estimate the vertical jump height, but the FT method cannot replace the gold standard, due to the large systematic bias. According to our results, the equations of each of the three jump modalities were presented in order to obtain a better estimation of the jump height.

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“…Research by Hartmann et al [14] on variable range of motion squats questions the necessity to use partial ranges like the ¼ squat, while others are advocates of this method [13,34]. Five of the coaches used parallel or above range of movement (ROM) squats, while one coach promoted the use of full ROM squats to facilitate adequate strength development.…”

Section: Theme One -Whatmentioning

confidence: 99%

Coaching sprinting: Expert coaches’ perception of resistance-based training

Bolger

Lyons

Harrison

et al. 2016

International Journal of Sports Science & Coaching

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The aim of this study was to explore expert coaches' perceptions of resistance-based training for sprinting. This research posed three broad questions: i) What resistance exercises are being performed by competitive sprinters? ii) Why coaches have selected these exercises over others? iii) How athletics coaches control and implement their use in training? Participants for the study comprised of seven expert track and field sprint coaches. Findings indicated that the coaches used a variety of resistance-based training including variations of the squat, Olympic weightlifting movements and deadlift, along with resisted running in the form of weighted jackets, hill running and weighted sleds. They also used plyometric variations of bounding and specific drills. Particular emphasis was drawn towards variations of the squat and how exercises transferred from the weights room to the track. All coaches changed exercises to complement the focus from off-season to in-season. The main finding of this study relates to the current dearth of research to support evidence based resistance exercise prescription for sprinters.Key Words: Coaches, Perceptions, Weight Training, Resistance-based Training, Sprinting, Track and Field Athletics. INTRODUCTIONThe area of coaching science and coaches' knowledge about training has become more popular in recent years. The breath of research has predominantly been quantitative in nature, ranging from the biomechanics of running [1] to the effect of resistance-based training on sprint performance in general [2,3]. Qualitatively, research has focused on the pedagogy [4,5], sociology [6] and psychology of coaching [7], with few studies focusing specifically on sprint coaches [7,8]. The framework for this paper is to explore coaches' views on resistance training, it will ascertain what, why and how coaches select and monitor their resistance-based training for sprinters. This approach is flexible in nature and allows for further exploration of the coaches' rationale for using different training methods using a survey style approach [9,10].

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Influence of Squatting Depth on Jumping Performance

Cited by 94 publications

References 90 publications

The Impact of Back Squat and Leg-Press Exercises on Maximal Strength and Speed-Strength Parameters

The Impact of Back Squat and Leg-Press Exercises on Maximal Strength and Speed-Strength Parameters

Measurement errors when estimating the vertical jump height with flight time using photocell devices: the example of Optojump

Coaching sprinting: Expert coaches’ perception of resistance-based training

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