Restricted access

Purchase article

USD $24.95

Student 1 year subscription

USD $107.00

1 year subscription

USD $142.00

Student 2 year subscription

USD $203.00

2 year subscription

USD $265.00

Purpose: To determine the reliability and variability of the Dynamic Strength Index (DSI) calculated from squat-jump (SJ) vs countermovement-jump (CMJ) peak force (PF) and to compare DSI values between methods. Methods: Male youth soccer and rugby league players (N = 27; age 17.2 ± 0.7 y, height 173.9 ± 5.7 cm, body mass 71.1 ± 7.2 kg) performed 3 trials of the SJ, CMJ, and isometric midthigh pull (IMTP) on 2 separate days. DSI was calculated by dividing the PF during each jump by the IMTP PF. Results: DSI-SJ exhibited moderate (intraclass correlation coefficient [ICC] = .419) within-session reliability and high variability (percentage coefficient of variation [%CV] = 15.91) during session 1; however, this improved noticeably during session 2 (ICC = .948, %CV = 4.03). In contrast, DSI-CMJ showed nearly perfect within-session reliability (ICC = .920–.952) and low variability (%CV = 3.80–4.57) for both sessions. Moreover, DSI-SJ values demonstrated a small yet significant increase between sessions (P = .01, d = 0.37), whereas only a trivial and nonsignificant increase was observed for DSI-CMJ between sessions (P = .796, d = 0.07). Between-sessions reliability was very high for the DSI-SJ (ICC = .741) and nearly perfect for the DSI-CMJ (ICC = .924). There was no significant or meaningful difference (P = .261, d = 0.12) between DSI-SJ (0.82 ± 0.18) and DSI-CMJ (0.84 ± 0.15). Conclusions: Practitioners should use DSI-CMJ, as it is a more reliable measure than DSI-SJ, although it produces similar ratios.

Comfort, Thomas, Dos’Santos, Jones, and McMahon are with the Directorate of Sport, Exercise and Physiotherapy, University of Salford, Salford, United Kingdom. Suchomel is with the Dept of Human Movement Sciences, Carroll University, Waukesha, WI.

Comfort (p.comfort@salford.ac.uk) is corresponding author.
International Journal of Sports Physiology and Performance
Article Sections
References
  • 1.

    Suchomel TJNimphius SStone MH. The importance of muscular strength in athletic performance. Sports Med. 2016;46(10):14191449. PubMed doi:10.1007/s40279-016-0486-0

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 2.

    Comfort PBullock NPearson SJ. A comparison of maximal squat strength and 5-, 10-, and 20-meter sprint times, in athletes and recreationally trained men. J Strength Cond Res. 2012;26(4):937940. PubMed doi:10.1519/JSC.0b013e31822e5889

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 3.

    Comfort PHaigh AMatthews MJ. Are changes in maximal squat strength during preseason training reflected in changes in sprint performance in rugby league players? J Strength Cond Res. 2012;26(3):772776. PubMed doi:10.1519/JSC.0b013e31822a5cbf

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 4.

    Styles WJMatthews MJComfort P. Effects of strength training on squat and sprint performance in soccer players. J Strength Cond Res. 2015;30(6):15341539. doi:10.1519/JSC.0000000000001243

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 5.

    Thomas CJones PARothwell JChiang CYComfort P. An investigation into the relationship between maximum isometric strength and vertical jump performance. J Strength Cond Res. 2015;29(8):21762185. PubMed doi:10.1519/JSC.0000000000000866

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 6.

    Hori NNewton RUAndrews WAKawamori NMcGuigan MRNosaka K. Does performance of hang power clean differentiate performance of jumping, sprinting, and changing of direction? J Strength Cond Res. 2008;22(2):412418 PubMed doi:10.1519/JSC.0b013e318166052b

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 7.

    Nimphius SMcGuigan MRNewton RU. Relationship between strength, power, speed, and change of direction performance of female softball players. J Strength Cond Res. 2010;24(4):885895. PubMed doi:10.1519/JSC.0b013e3181d4d41d

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 8.

    Spiteri TNimphius SHart NHSpecos CSheppard JMNewton RU. Contribution of strength characteristics to change of direction and agility performance in female basketball athletes. J Strength Cond Res. 2014;28(9):24152423. PubMed doi:10.1519/JSC.0000000000000547

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 9.

    Secomb JLLundgren LEFarley ORTran TTNimphius SSheppard JM. Relationships between lower-body muscle structure and lower-body strength, power, and muscle-tendon complex stiffness. J Strength Cond Res. 2015;29(8):22212228. PubMed doi:10.1519/JSC.0000000000000858

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 10.

    Secomb JLNimphius SFarley ORLundgren LTran TTSheppard JM. Lower-body muscle structure and jump performance of stronger and weaker surfing athletes. Int J Sports Physiol Perform. 2016;11:652657. PubMed doi:10.1123/ijspp.2015-0481

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 11.

    Nuzzo JLMcBride JMCormie PMcCaulley GO. Relationship between countermovement jump performance and multijoint isometric and dynamic tests of strength. J Strength Cond Res 2008;22(3):699707. PubMed doi:10.1519/JSC.0b013e31816d5eda

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 12.

    Faigenbaum ADMcFarland JEHerman REet al. Reliability of the one-repetition-maximum power clean test in adolescent athletes. J Strength Cond Res. 2012;26(2):432437. PubMed doi:10.1519/JSC.0b013e318220db2c

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 13.

    Comfort PMcMahon JJ. Reliability of maximal back squat and power clean performances in inexperienced athletes. J Strength Cond Res. 2015;29(11):30893096. PubMed doi:10.1519/JSC.0000000000000815

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 14.

    Haff GGRuben RPLider JTwine CCormie P. A comparison of methods for determining the rate of force development during isometric mid-thigh clean pulls. J Strength Cond Res. 2015;29(2):386395. PubMed doi:10.1519/JSC.0000000000000705

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 15.

    Dos’santos TJones PAKelly JMcMahon JJComfort PThomas C. Effect of sampling frequency on isometric midthigh-pull kinetics. Int J Sports Physiol Perform. 2016;11(2):255260. doi:10.1123/ijspp.2015-0222

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 16.

    Beckham GMizuguchi SCarter Cet al. Relationships of isometric mid-thigh pull variables to weightlifting performance. J Sports Med Phys Fitness. 2013;53(5):573581. PubMed

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 17.

    Beckham GKSato KMizuguchi SHaff GGStone MH. Effect of body position on force production during the isometric mid-thigh pull. J Strength Cond Res. 2018;23(1):4856. doi:10.1519/JSC.0000000000001968

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 18.

    Harris NKCronin JTaylor KLBoris JSheppard J. Understanding position transducer technology for strength and conditioning practitioners. Strength Cond J. 2010;32(4):6679. doi:10.1519/SSC.0b013e3181eb341b

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 19.

    Sheppard JChapman DTaylor K. An evaluation of a strength qulities assessment method for the lower body. J Aust Strength Cond. 2011;19(2):410.

    • Search Google Scholar
    • Export Citation
  • 20.

    Secomb JLFarley ORLundgren Let al. Associations between the performance of scoring manouvres and lower-body strength and power in elite surfers. Int J Sports Sci Coach. 2015;10(5):911918. doi:10.1260/1747-9541.10.5.911

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 21.

    Secomb JLNimphius SFarley ORLundgren LTran TSheppard J. Relationships between lower-body muscle structure and, lower-body strength, explosiveness and eccentric leg stiffness in adolescent athletes. J Sports Sci Med. 2015;14(4):691697. PubMed

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 22.

    Thomas CJones PAComfort P. Reliability of the Dynamic Strength Index in college athletes. Int J Sports Physiol Perform. 2015;10(5):542545. PubMed doi:10.1123/ijspp.2014-0255

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 23.

    Cormie PMcGuigan MRNewton RU. Adaptations in athletic performance after ballistic power versus strength training. Med Sci Sports Exerc. 2010;42(8):15821598. PubMed doi:10.1249/MSS.0b013e3181d2013a

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 24.

    Cormie PMcGuigan MRNewton RU. Influence of training status on power absorption & production during lower body stretch-shorten cycle movements. J Strength Cond Res. 2010;24(S):1. doi:10.1097/01.JSC.0000367087.27639.48

    • Search Google Scholar
    • Export Citation
  • 25.

    Bosco CKomi PVIto A. Prestretch potentiation of human skeletal muscle during ballistic movement. Acta Physiol Scand. 1981;111(2):135140. PubMed doi:10.1111/j.1748-1716.1981.tb06716.x

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 26.

    Bosco CViitasalo JTKomi PVLuhtanen P. Combined effect of elastic energy and myoelectrical potentiation during stretch-shortening cycle exercise. Acta Physiol Scand. 1982;114(4):557565. PubMeddoi:10.1111/j.1748-1716.1982.tb07024.x

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 27.

    Owen NJWatkins JKilduff LPBevan HRBennett MA. Development of a criterion method to determine peak mechanical power output in a countermovement jump. J Strength Cond Res. 2014;28(6):15521558. PubMed doi:10.1519/JSC.0000000000000311

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 28.

    Moir GL. Three different methods of calculating vertical jump height from force platform data in men and women. Meas Phys Educ Exerc Sci. 2014;12(4):207218. doi:10.1080/10913670802349766

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 29.

    Street GMcMillan SBoard WRasmussen MHeneghan JM. Sources of error in determining countermovement jump height with the impulse method. J Appl Biomech. 2001;17(1):4354. doi:10.1123/jab.17.1.43

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 30.

    McMahon JJRej SJComfort P. Sex differences in countermovement jump phase characteristics. Sports. 2017;5(1):8. doi:10.3390/sports5010008

  • 31.

    Haff GGCarlock JMHartman MJet al. Force–time curve characteristics of dynamic and isometric muscle actions of elite women olympic weightlifters. J Strength Cond Res. 2005;19(4):741748. PubMed

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 32.

    Haff GGStone MO’Bryant HSet al. Force–time dependent characteristics of dynamic and isometric muscle actions. J Strength Cond Res. 1997;11(4):269272.

    • Search Google Scholar
    • Export Citation
  • 33.

    Cormack SJNewton RUMcGuigan MRDoyle TL. Reliability of measures obtained during single and repeated countermovement jumps. Int J Sports Physiol Perform. 2008;3(2):131144. PubMed doi:10.1123/ijspp.3.2.131

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 34.

    Hopkins WGMarshall SWBatterham AMHanin J. Progressive statistics for studies in sports medicine and exercise science. Med Sci Sports Exerc. 2009;41(1):313. PubMed doi:10.1249/MSS.0b013e31818cb278

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 35.

    Hopkins WG. A scale of magnitudes of effect statistics. Sportsci.org [website]. 2006. http://sportsci.org/resource/stats/index.html. Accessed August 5 2015.

    • Search Google Scholar
    • Export Citation
  • 36.

    Suchomel TJBailey CASole CJGrazer JLBeckham GK. Using Reactive Strength Index-Modified as an explosive performance measurement tool in Division I athletes. J Strength Cond Res. 2015;29(4):899904. PubMed doi:10.1519/JSC.0000000000000743

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 37.

    Suchomel TJSole CJStone MH. Comparison of methods that assess lower-body stretch-shortening cycle utilization. J Strength Cond Res. 2016;30(2):547554. PubMed doi:10.1519/JSC.0000000000001100

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
Article Metrics
All Time Past Year Past 30 Days
Abstract Views 132 132 53
Full Text Views 25 25 11
PDF Downloads 14 14 4
Altmetric Badge
PubMed
Google Scholar