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Biomechanics/Neuromuscular

(2) Countermovement Jump Testing: Eccentric-to-Concentric Ratio

Saturday, July 15, 2023
10:00 AM – 11:30 AM East Coast USA Time
Location: Milano III-IV

    Poster Presenter(s)

  • Antonio Squillante, M.S. CSCS*D RSCC

    Researcher
    University of Southern California
    La Crescenta, California, United States

    • Author(s)

  • RC

    Roberto Cala'

    Sports Scientist
    Atalanta Training Lab - Atalanta Calcio
    Brescia, Lombardia, Italy

  • MS

    Matteo Sapa

    Sports Scientist
    Atalanta Training Lab - Atalanta Calcio
    Brescia, Lombardia, Italy

  • AP

    Alberto Pasini

    Sports Scientist
    Atalanta Training Lab - Atalanta Calcio
    Brescia, Lombardia, Italy

Abstract Details: Jump height in a standard countermovement jump (CMJ) is used to assess lower body strength and power. Lower body strength alone, however, does not explain the difference in jump height between athletes of similar age and level of experience. The ability to utilize the stretch-shortening cycle (SCC) has been addressed as a limiting factor in jumping performance. Greater eccentric force being generated during the unweighted phase has been shown to positively contribute to increase concentric impulse and jump height.

Purpose: This study aims to determine the correlation between the eccentric-to-concentric ratio - the ratio between eccentric and concentric contraction time measured in milliseconds (ECC:CON) - and jump height in a group of U19 male soccer players.

Method: A total of 20 young professional soccer players   (age 17 ± 1.8, height 171 ± 4 cm, body mass 72.2 ± 12.3 kg)  performed three CMJ on force plate sampling at 1000 Hz (ForceDecks, VALD Performance, Australia). The best jump height was recorded for analysis. ECC:CON was calculated by dividing eccentric contraction time during the unweighted phase and concentric contraction time during take-off.

Results: Based on jump height in the CMJ (average: 40.12 cm), subjects were divided into 2 groups: subjects who scored above the average in the CMJ  (Group A) and subjects who scored below the average in the CMJ (Group B). Using a Pearson correlation analysis, jump height was compared to ECC:CON. In Group A jump height increases linearly with an increase in ECC:CON  suggesting a more effective use of the unweighted phase associated with a longer eccentric muscle contraction (r=0.67, df=9, p< 0.05). In Group B a weak, negative correlation emerged between jump height and ECC:CON suggesting a more erratic and less efficient approach to jumping mechanics that relies on concentric strength rather than a more effective utilization of the SCC (r=-0.34, df=9, p< 0.05) 

Conclusion: Greater impulse and greater force at take-off undoubtedly contribute to increased jump height in a standard CMJ. A better and more efficient jumping mechanics is associated with a relatively longer eccentric muscle contraction during the unweighted phase of the jump as opposed to a shorter, faster concentric muscle action at take off. Greater eccentric force being generated over a longer period of time can contribute to a more efficient use of the SSC and increase jump height.

Acknowledgements: None