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Inter-relationships between machine squat-jump strength, force, power and 10 m sprint times in trained sportsmen.
J Sports Med Phys Fitness. 2010 Mar; 50(1):37-42.JS

Abstract

AIM

Strength and conditioning practitioners appear focussed on developing maximal strength based on the premise that it underpins explosive muscular performance. Investigation into the relationship between strength and a multitude of explosive power measures is limited though. Furthermore, the relationship of explosive force and power with functional performance is unclear.

METHODS

We examined the inter-relationships between maximal strength and explosive measures of force and power at different loads. Also investigated were the relationships between explosive measures and 10-m sprinting ability. Forty elite-level well-trained rugby union and league athletes performed 10-m sprints followed by bilateral concentric-only machine squat-jumps at 20 and 80%1RM. The magnitudes of the inter-relationships between groups of force measures, power measures and sprint times were interpreted using Pearson correlation coefficients, which had uncertainty (90% confidence limits) of approximately +/-0.25. Measures investigated included peak force, peak power, rate of force development, and some of Zatsiorsky's explosive measures, all expressed relative to body mass.

RESULTS

The relationship between maximal strength and peak power was moderate at 20 %1RM (r=0.32) but trivial at 80 %1RM (r=-0.03). Practically no relationship between any of the explosive measures and 10-m sprint ability was observed (r=-0.01 to 0.06).

CONCLUSION

Although correlations do not imply cause and effect, we speculate that the common practice of focussing on high levels of maximal strength in a machine squat to improve power output may be misguided. Our results also cast doubt on the efficacy of increasing explosive force and power in a machine squat-jump with the intention of improving sprint ability in well-trained athletes.

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Authors+Show Affiliations

Harris NK
Sport Performance Research Institute New Zealand, AUT University, Auckland, New Zealand. nigel.harris@aut.ac.nz
Cronin JB
No affiliation info available
Hopkins WG
No affiliation info available
Hansen KT
No affiliation info available

MeSH

AdultBiomechanical PhenomenaConfidence IntervalsFootballHumansLegMaleMuscle ContractionMuscle StrengthMuscle, SkeletalPilot ProjectsRunningStatistics as TopicTime FactorsWeight Lifting

Pub Type(s)

Journal Article

Language

eng

PubMed ID

20308970

Citation

Harris, Nigel K., et al. "Inter-relationships Between Machine Squat-jump Strength, Force, Power and 10 M Sprint Times in Trained Sportsmen." The Journal of Sports Medicine and Physical Fitness, vol. 50, no. 1, 2010, pp. 37-42.
Harris NK, Cronin JB, Hopkins WG, et al. Inter-relationships between machine squat-jump strength, force, power and 10 m sprint times in trained sportsmen. J Sports Med Phys Fitness. 2010;50(1):37-42.
Harris, N. K., Cronin, J. B., Hopkins, W. G., & Hansen, K. T. (2010). Inter-relationships between machine squat-jump strength, force, power and 10 m sprint times in trained sportsmen. The Journal of Sports Medicine and Physical Fitness, 50(1), 37-42.
Harris NK, et al. Inter-relationships Between Machine Squat-jump Strength, Force, Power and 10 M Sprint Times in Trained Sportsmen. J Sports Med Phys Fitness. 2010;50(1):37-42. PubMed PMID: 20308970.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Inter-relationships between machine squat-jump strength, force, power and 10 m sprint times in trained sportsmen. AU - Harris,Nigel K, AU - Cronin,J B, AU - Hopkins,W G, AU - Hansen,K T, PY - 2010/3/24/entrez PY - 2010/3/24/pubmed PY - 2011/1/7/medline SP - 37 EP - 42 JF - The Journal of sports medicine and physical fitness JO - J Sports Med Phys Fitness VL - 50 IS - 1 N2 - AIM: Strength and conditioning practitioners appear focussed on developing maximal strength based on the premise that it underpins explosive muscular performance. Investigation into the relationship between strength and a multitude of explosive power measures is limited though. Furthermore, the relationship of explosive force and power with functional performance is unclear. METHODS: We examined the inter-relationships between maximal strength and explosive measures of force and power at different loads. Also investigated were the relationships between explosive measures and 10-m sprinting ability. Forty elite-level well-trained rugby union and league athletes performed 10-m sprints followed by bilateral concentric-only machine squat-jumps at 20 and 80%1RM. The magnitudes of the inter-relationships between groups of force measures, power measures and sprint times were interpreted using Pearson correlation coefficients, which had uncertainty (90% confidence limits) of approximately +/-0.25. Measures investigated included peak force, peak power, rate of force development, and some of Zatsiorsky's explosive measures, all expressed relative to body mass. RESULTS: The relationship between maximal strength and peak power was moderate at 20 %1RM (r=0.32) but trivial at 80 %1RM (r=-0.03). Practically no relationship between any of the explosive measures and 10-m sprint ability was observed (r=-0.01 to 0.06). CONCLUSION: Although correlations do not imply cause and effect, we speculate that the common practice of focussing on high levels of maximal strength in a machine squat to improve power output may be misguided. Our results also cast doubt on the efficacy of increasing explosive force and power in a machine squat-jump with the intention of improving sprint ability in well-trained athletes. SN - 0022-4707 UR - https://www.unboundmedicine.com/medline/citation/20308970/Inter_relationships_between_machine_squat_jump_strength_force_power_and_10_m_sprint_times_in_trained_sportsmen_ L2 - http://www.minervamedica.it/index2.t?show=R40Y2010N01A0037 DB - PRIME DP - Unbound Medicine ER -