Relationship Between Dynamic Strength Index and Early Force Production of Isometric Mid-Thigh Pull

Abstract

Purpose

Dynamic strength index (DSI) and percentage of isometric mid-thigh pull (IMTP) peak force (PF) produced during early epoch, expressed as a percentage of net PF (%PF), are useful strength assessments to evaluate an athlete’s training status. Due to the similarity in diagnosis that the DSI ratio and %PF provides, it is not known whether %PF can reflect closely to an athlete’s DSI ratio. Therefore, the aim of this study is to establish the relationship between DSI and %PF.

Methods

Thirty-seven national athletes (age = 22.9 ± 3.12 years; height = 1.73 ± 0.08 m; body mass = 69.1 ± 10.68 kg) were recruited for this study. Participants performed the countermovement jump test (CMJ) and isometric mid-thigh pull (IMTP) during both familiarisation and testing sessions. IMTP and CMJ force–time variables were collected to compute the DSI ratio and %PF for analysis.

Results

Trivial to small correlations between DSI and %PF was observed across all epochs (50 ms: r = 0.09, 95% CI − 0.241–0.402, P > 0.598; 100 ms: r = − 0.021, 95% CI − 0.343–0.305, P > 0.9; 150 ms: r = − 0.058, 95% CI − 0.375–0.271, P > 0.734; 200 ms: r = 0.126, 95% CI − 0.207–0.432, P > 0.458).

Conclusion

DSI ratio and %PF are two distinct monitoring tools and not interchangeable. Both DSI and the percentage of IMTP net PF at early time points are useful in evaluating athletes’ previous training phases and current physical performance.

Keywords

Countermovement jump / Peak force / Force epoch

References

[1] Beattie K, Carson BP, Lyons M, Rossiter A, Kenny IC. The effect of strength training on performance indicators in distance runners. J Strength Cond Res, 2017, 31(1): 9-23

[2] Beckham G, Mizuguchi S, Carter C, Sato K, Ramsey M, Lamont H, Hornsby G, Haff G, Stone M. Relationships of isometric mid-thigh pull variables to weightlifting performance. J Sports Med Phys Fitness, 2013, 53(5): 573-581

[3] Bourgeois F, Gamble P, Gill N, Mcguigan M. Effects of a six-week strength training programme on change of direction performance in youth team sport athletes. Sports, 2017, 5(4): 83

[4] Brady CJ, Harrison AJ, Comyns TM. A review of the reliability of biomechanical variables produced during isometric mid-thigh pull and isometric squat and the reporting of normative data. Sports Biomech, 2020, 19(1): 1-25

[5] Buckthorpe M, Pain MT, Folland JP. Central fatigue contributes to the greater reductions in explosive than maximal strength with high-intensity fatigue. Exp Physiol, 2014, 99(7): 964-973

[6] Comfort P, Dosʼsantos T, Beckham GK, Stone MH, Guppy SN, Haff GG. Standardization and methodological considerations for the isometric midthigh pull. Strength Cond J, 2019, 41(2): 57-79

[7] Comfort P, Dos’Santos T, Jones PA, McMahon JJ, Suchomel TJ, Bazyler C, Stone MH. Normalization of early isometric force production as a percentage of peak force during multijoint isometric assessment. Int J Sports Physiol Perform, 2020, 15(4): 478-482

[8] Comfort P, Thomas C, Dos’Santos T, Jones PA, Suchomel TJ, McMahon JJ. Comparison of methods of calculating dynamic strength index. Int J Sports Physiol Perform, 2018, 13(3): 320-325

[9] Comfort P, Thomas C, Dos’Santos T, Suchomel T, Jones P, McMahon J. Changes in dynamic strength index in response to strength training. Sports, 2018, 6(4): 176

[10] Cormack SJ, Newton RU, McGuigan MR, Doyle TLA. Reliability of measures obtained during single and repeated countermovement jumps. Int J Sports Physiol Perform, 2008, 3(2): 131-144

[11] Crowley E, Harrison AJ, Lyons M. The impact of resistance training on swimming performance: a systematic review. Sports Med, 2017, 47(11): 2285-2307

[12] Dos' Santos T, Jones PA, Comfort P, Thomas C. Effect of different onset thresholds on isometric midthigh pull force-time variables. J Strength Cond Res, 2017, 31(12): 3463-3473

[13] Haff GG, Ruben RP, Lider J, Twine C, Cormie 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): 386-395

[14] Hakkinen K, Myllyla E. Acute effect of muscle fatigue and recovery on force production and relaxation in endurance, power and strength athletes. J Sports Med Phys Fitness, 1990, 30(1): 5-12

[15] Heishman A, Brown B, Daub B, Miller R, Freitas E, Bemben M. The influence of countermovement jump protocol on reactive strength index modified and flight time: contraction time in collegiate basketball players. Sports, 2019, 7(2): 37

[16] Hopkins WG, Marshall SW, Batterham AM, Hanin J. Progressive statistics for studies in sports medicine and exercise science. Med Sci Sports Exerc, 2009, 41(1): 3-13

[17] James LP, Talpey SW, Young WB, Geneau MC, Newton RU, Gastin PB. Strength classification and diagnosis: not all strength is created equal. Strength Cond J, 2022, 45(3): 333-341

[18] Kim M, Choi J, Gim M, Kim Y, Yoo K. Effects of different types of exercise on muscle activity and balance control. J Phys Ther Sci, 2015, 27(6): 1875-1881

[19] Koo TK, Li MY. A guideline of selecting and reporting intraclass correlation coefficients for reliability research. J Chiropr Med, 2016, 15(2): 155-163

[20] Linthorne NP. Analysis of standing vertical jumps using a force platform. Am J Phys, 2001, 69(11): 1198-1204

[21] Lum D. Effects of performing endurance and strength or plyometric training concurrently on running economy and performance. Strength Cond J, 2016, 38(3): 26-35

[22] Lum D, Chua K, Aziz AR. Isometric mid-thigh pull force-time characteristics: a good indicator of running performance. J Trainol, 2020, 9(2): 54-59

[23] Lum D, Comfort P, Barbosa TM, Balasekaran G. Comparing the effects of plyometric and isometric strength training on dynamic and isometric force-time characteristics. Biol Sport, 2022, 39(1): 189-197

[24] McMahon JJ, Suchomel TJ, Lake JP, Comfort P. Understanding the key phases of the countermovement jump force-time curve. Strength Cond J, 2018, 40(4): 96-106

[25] Nazmi N, Rahman MA, Yamamoto S, Ahmad S, Zamzuri H, Mazlan S. A review of classification techniques of EMG signals during isotonic and isometric contractions. Sensors, 2016, 16(8): 1304

[26] Nuzzo JL, Mcbride JM, Cormie P, McCaulley GO. Relationship between countermovement jump performance and multi-joint isometric and dynamic tests of strength. J Strength Cond, 2008, 22(3): 699-707

[27] Petrigna L, Karsten B, Marcolin G, Paoli A, Antona G, Palma A, Bianco A. A review of countermovement and squat jump testing methods in the context of public health examination in adolescence: reliability and feasibility of current testing procedures. Front Physiol, 2019, 10: 1384

[28] Secomb JL, Nimphius S, Farley OR, Lundgren LE, Tran TT, Sheppard JM. 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): 691

[29] Sheppard JM, Chapman D, Taylor K-L. An evaluation of a strength qualities assessment method for the lower body. J Australian Strength Cond, 2011, 19(2): 4-10

[30] Siff MZatsiorsky V. Biomechanical foundations of strength and power training. Biomechanics in sport, 2001, London, Blackwell Scientific Ltd103-139

[31] Stone MH. Position statement: explosive exercises and training. Natl Strength Cond Assoc J, 1993, 15(3): 7-15

[32] Suchomel TJ, Nimphius S, Stone MH. The importance of muscular strength in athletic performance. Sports Med (Auckland, N.Z.), 2016, 46(10): 1419-1449

[33] Suchomel T, Sole C, Bellon C, Stone M. Dynamic strength index: relationships with common performance variables and contextualization of training recommendations. J Hum Kinet, 2020, 74: 59-70

[34] Thomas C, Comfort P, Chiang C, Jones PA. Relationship between isometric mid-thigh pull variables and sprint and change of direction performance in collegiate athletes. J Trainol, 2015, 4(1): 6-10

[35] Thomas C, Comfort P, Jones PA, Dos’Santos T. A comparison of isometric mid-thigh pull strength, vertical jump, sprint speed, and change of direction speed in academy netball players. Int J Sports Physiol Perform, 2016, 12(7): 916-921

[36] Thomas C, Dos’Santos T, Jones P. A comparison of dynamic strength index between team-sport athletes. Sports, 2017, 5(3): 71

[37] Thomas C, Jones PA, Comfort P. Reliability of the dynamic strength index in college athletes. Int J Sports Physiol Perform, 2015, 10(5): 542-545

[38] Thomas C, Jones PA, Rothwell J, Chiang CY, Comfort P. An investigation into the relationship between maximum isometric strength and vertical jump performance. J Strength Cond Res, 2015, 29(8): 2176-2185

[39] Wilson GJ, Lyttle AD, Ostrowski KJ, Murphy AJ. Assessing dynamic performance: a comparison of rate of force development tests. J Strength Cond Res, 1995, 9(3): 176-181

RIGHTS & PERMISSIONS

Beijing Sport University