We found less than 3% differences between D and ND legs for peak torque values, which is the same as the accuracy of the force measuring system of isokinetic torques of 3% (14). Hence, we could not conclude that there is a real difference between D and ND legs for handball and football players. Both handball and football players demonstrated significantly greater hamstring strength on their D leg compared with ND leg. As expected, smaller SEMs have been reported for right and left legs differences (or D and ND legs) for knee extension and flexion (5% and 2%) (9).
A previous study has reported that male football players were more likely to injure their D leg while kicking the ball, whereas female football players injured their ACL more often while standing on their ND leg (3). Handball players would often state that their D leg is their jumping leg (most often left leg), but would answer the right leg if they were asked which leg they kicked a ball with. Football players would most often state that their D leg is the leg they kick with and that would be their strongest leg (24).
Our normative data for handball and football players are in line with a few other studies on female handball and football players but with smaller sample sizes (Table 3). No differences were disclosed between our knee extension peak torque data and those reported by Andrade et al. (1) for handball or football players. Lund-Hanssen et al. (26) reported greater quadriceps muscle strength for handball players (p = 0.001) compared with our data, but similar hamstring strength data, also when normalized to body mass (Table 3). Finally, isokinetic peak torque data for the nonathletic populations disclosed significantly lower knee extension and flexion peak torques compared with our handball and football players (Table 3 and Figure 6) (8,17). Our study on normative isokinetic muscle strength data for knee extension and flexion adds to the body of knowledge with a large group of healthy handball and football players compared with previously published studies (Table 3). Lund-Hanssen et al. (26) from 1996 is the only study with a large sample size (n = 144), but they reported only data on handball players.
Reporting only isokinetic peak torque value has limitations. Previous studies have highlighted the importance of reporting quadriceps muscle performance during the whole ROM, identifying possible irregularities or asymmetries of muscle performance (12). Studies have identified the largest strength deficits in ACL-injured individuals between 40° of knee flexion toward full extension and not at peak torque (approximately 60° of knee flexion) (12,40). The use of isokinetic angle–specific torque values thus provide more information on quadriceps and hamstrings muscle performance than reporting a single peak torque value in ACL-, meniscus-, and articular cartilage–injured individuals (12). Hence, normative angle–specific curves shown in this study could be used clinically to compare isokinetic curves in knee-injured athletes. The whole isokinetic knee extension and flexion torque curves in healthy athletes can thus be used as reference curves in comparison to those with knee injury (Figures 2–5).
These normative isokinetic knee extension and flexion muscle strength values during knee ROM of healthy, elite, female handball and football players can be used to set rehabilitation goals for muscle strength after injury and enable comparison with uninjured legs. This study included a large number of subjects and showed that there are sport-specific differences in quadriceps and hamstring muscle strength for healthy individuals.
The Oslo Sports Trauma Research Center has been established at the Norwegian School of Sport Sciences through generous grants from the Royal Norwegian Ministry of Culture, the South-Eastern Norway Regional Health Authority, the International Olympic Committee, the Norwegian Olympic Committee & Confederation of Sport, and Norsk Tipping AS. The authors have no conflicts of interest to disclose. The study was approved by the Regional Committee for Medical Research Ethics; South-Eastern Norway Regional Health Authority, Norway, and by the Norwegian Social Science Data Services.
1. Andrade MS, De Lira CA, Koffes FC, Mascarin NC, Benedito-Silva AA, Da Silva AC. Isokinetic hamstrings-to-quadriceps peak torque ratio: The influence of sport modality, gender, and angular velocity. J Sports Sci 30: 547–553, 2012.
2. Ardern CL, Pizzari T, Wollin MR, Webster KE. Hamstrings strength imbalance in professional football (soccer) players in Australia. J Strength Cond Res 29: 997–1002, 2015.
3. Brophy R, Silvers HJ, Gonzales T, Mandelbaum BR. Gender influences: The role of leg dominance in ACL injury among soccer players. Br J Sports Med 44: 694–697, 2010.
4. Buchanan PA, Vardaxis VG. Lower-extremity strength profiles and gender-based classification of basketball players ages 9-22 years. J. Strength. Cond. Res 23:406–419, 2009.
5. Chung KS, Ha JK, Yeom CH, Ra HJ, Lim JW, Kwon MS, Kim JG. Are muscle strength and function of the uninjured lower limb weakened after anterior cruciate ligament Injury? Two-year follow-up after reconstruction. Am J Sports Med 43: 3013–3021, 2015.
6. Cometti G, Maffiuletti NA, Pousson M, Chatard JC, Maffulli N. Isokinetic strength and anaerobic power of elite, subelite and amateur French soccer players. Int J Sports Med 22: 45–51, 2001.
7. Coombs R, Garbutt G. Developments in the use of the hamstring/quadriceps ratio for the assessment of muscle balance. J Sports Sci Med 1: 56–62, 2002.
8. Danneskiold-Samsoe B, Bartels EM, Bulow PM, Lund H, Stockmarr A, Holm CC, Watjen I, Appleyard M, Bliddal H. Isokinetic and isometric muscle strength in a healthy population with special reference to age and gender. Acta Physiol (Oxf) 197(Suppl 673): 1–68, 2009.
9. de Carvalho Froufe Andrade AC, Caserotti P, de Carvalho CM, de Azevedo Abade EA, da Eira Sampaio AJ. Reliability of concentric, eccentric and isometric knee extension and flexion when using the REV9000 isokinetic dynamometer. J Human Kinetics 37: 47–53, 2013.
10. Decker MJ, Torry MR, Wyland DJ, Sterett WI, Richard Steadman J. Gender differences in lower extremity kinematics, kinetics and energy absorption during landing. Clin Biomech (Bristol, Avon) 18: 662–669, 2003.
11. Drouin JM, Valovich-mcLeod TC, Shultz SJ, Gansneder BM, Perrin DH. Reliability and validity of the Biodex system 3 pro isokinetic dynamometer velocity, torque and position measurements. Eur J Appl Physiol 91: 22–29, 2004.
12. Eitzen I, Eitzen TJ, Holm I, Snyder-Mackler L, Risberg MA. Anterior cruciate ligament-deficient potential copers and noncopers reveal different isokinetic quadriceps strength profiles in the early stage after injury. Am J Sports Med 38: 586–593, 2010.
13. Evangelidis PE, Pain MT, Folland J. Angle-specific hamstring-to-quadriceps ratio: A comparison of football players and recreationally active males. J Sports Sci 33: 309–319, 2015.
14. Farrell M, Richards JG. Analysis of the reliability and validity of the kinetic communicator exercise device. Med Sci Sports Exerc 18: 44–49, 1986.
15. Fillyaw M, Bevins T, Fernandez L. Importance of correcting isokinetic peak torque for the effect of gravity when calculating knee flexor to extensor muscle ratios. Phys Ther 66:23–31, 1986.
16. Grindem H, Snyder-Mackler L, Moksnes H, Engebretsen L, Risberg MA. Simple decision rules can reduce reinjury risk by 84% after ACL reconstruction: The Delaware-Oslo ACL cohort study. Br J Sports Med 50: 804–808, 2016.
17. Harbo T, Brincks J, Andersen H. Maximal isokinetic and isometric muscle strength of major muscle groups related to age, body mass, height, and sex in 178 healthy subjects. Eur J Appl Physiol 112: 267–275, 2012.
18. Holm I, Risberg MA, Aune AK, Tjomsland O, Steen H. Muscle strength recovery following anterior cruciate ligament reconstruction. Isokinet Exerc Sci 8: 57–63, 2000.
19. Kim HJ, Lee JH, Ahn SE, Park MJ, Lee DH. Influence of anterior cruciate ligament tear on thigh muscle strength and hamstring-to-quadriceps ratio: A meta-analysis. PLoS One 11: e0146234, 2016.
20. Konishi Y, Konishi H, Fukubayashi T. Gamma loop dysfunction in quadriceps on the contralateral side in patients with ruptured ACL. Med Sci Sports Exerc 35: 897–900, 2003.
21. Kristianslund E, Faul O, Bahr R, Myklebust G, Krosshaug T. Sidestep cutting technique and knee abduction loading: Implications for ACL prevention exercises. Br J Sports Med 48: 779–783, 2014.
22. Krosshaug T, Steffen K, Kristianslund E, Nilstad A, Mok KM, Myklebust G, Andersen TE, Holme I, Engebretsen L, Bahr R. The vertical drop jump is a poor screening test for ACL injuries in female elite soccer and handball players: A prospective cohort study of 710 athletes
. Am J Sports Med 44: 874–883, 2016.
23. Kurdak SS, Ozgunen K, Adas U, Zeren C, Aslangiray B, Yazici Z, Korkmaz S. Analysis of isokinetic knee extension/flexion in male elite adolescent wrestlers. J Sports Sci Med 4: 489–498, 2005.
24. Lanshammar K, Ribom EL. Differences in muscle strength in dominant and non-dominant leg in females aged 20-39 years–a population-based study. Phys Ther Sport 12: 76–79, 2011.
25. Leyva A, Balachandran A, Signorile JF. Lower-body torque and power declines across six decades in three hundred fifty-seven men and women: a cross-sectional study with normative values
. J Strength. Cond. Res 30:141–158, 2016.
26. Lund-Hanssen H, Gannon J, Engebretsen L, Holen K, Hammer S. Isokinetic muscle performance in healthy female handball players and players with a unilateral anterior cruciate ligament reconstruction. Scand J Med Sci Sports 6: 172–175, 1996.
27. Myklebust G, Maehlum S, Holm I, Bahr R. A prospective cohort study of anterior cruciate ligament injuries in elite Norwegian team handball. Scand J Med Sci Sports 8: 149–153, 1998.
28. Neder JA, Nery LE, Shinzato GT, Andrade MS, Peres C, Silva AC. Reference values
for concentric knee isokinetic strength and power in nonathletic men and women from 20 to 80 years old. J Orthop Sports Phys Ther 29: 116–126, 1999.
29. Niederer D, Wilke J, Vogt L, Banzer W. Return to play after injuries—A survey on the helpfulness of various forms of assistance in the shared decision-making process in semi-professional athletes
in Germany. Arch Phys Med Rehabil 99: 690–698, 2017.
30. Oiestad BE, Holm I, Aune AK, Gunderson R, Myklebust G, Engebretsen L, Fosdahl MA, Risberg MA. Knee function and prevalence of knee osteoarthritis after anterior cruciate ligament reconstruction: A prospective study with 10 to 15 years of follow-up. Am J Sports Med 38: 2201–2210, 2010.
31. Orchard J, Marsden J, Lord S, Garlick D. Preseason hamstring muscle weakness associated with hamstring muscle injury in Australian footballers. Am J Sports Med 25: 81–85, 1997.
32. Palmieri-Smith RM, Lepley LK. Quadriceps strength asymmetry after anterior cruciate ligament reconstruction alters knee joint biomechanics and functional performance at time of return to activity. Am J Sports Med 43: 1662–1669, 2015.
33. Pincivero DM, Gandaio CM, Ito Y. Gender-specific knee extensor torque, flexor torque, and muscle fatigue responses during maximal effort contractions. Eur J Appl Physiol 89: 134–141, 2003.
34. Probst MM, Fletcher R, Seelig DS. A comparison of lower-body flexibility, strength, and knee stability between karate athletes
and active controls. J Strength Cond Res 21: 451–455, 2007.
35. Ruas CV, Minozzo F, Pinto MD, Brown LE, Pinto RS. Lower-extremity strength ratios of professional soccer players according to field position. J Strength Cond Res 29: 1220–1226, 2015.
36. Sole G, Hamren J, Milosavljevic S, Nicholson H, Sullivan SJ. Test-retest reliability of isokinetic knee extension and flexion. Arch Phys Med Rehabil 88: 626–631, 2007.
37. Steffen K, Nilstad A, Kristianslund EK, Myklebust G, Bahr R, Krosshaug T. Association between lower extremity muscle strength and noncontact ACL. Injuries Med Sci Sports Exerc 48: 2082–2089, 2016.
38. Steffen K, Nilstad A, Krosshaug T, Pasanen K, Killingmo A, Bahr R. No association between static and dynamic postural control and ACL injury risk among female elite handball and football players: A prospective study of 838 players. Br J Sports Med 51: 253–259, 2017.
39. Sward P, Kostogiannis I, Roos H. Risk factors for a contralateral anterior cruciate ligament injury. Knee Surg Sports Traumatol Arthrosc 18: 277–291, 2010.
40. Thomee R, Kaplan Y, Kvist J, Myklebust G, Risberg MA, Theisen D, Tsepis E, Werner S, Wondrasch B, Witvrouw E. Muscle strength and hop performance criteria prior to return to sports after ACL reconstruction. Knee Surg Sports Traumatol Arthrosc 19: 1798–1805, 2011.
41. Urbach D, Awiszus F. Impaired ability of voluntary quadriceps activation bilaterally interferes with function testing after knee injuries. A twitch interpolation study. Int J Sports Med 23: 231–236, 2002.
42. van der Horst N, Backx F, Goedhart EA, Huisstede BM. Return to play after hamstring injuries in football (soccer): A worldwide Delphi procedure regarding definition, medical criteria and decision-making. Br J Sports Med 51: 1583–1591, 2017.
43. Wright RW, Magnussen RA, Dunn WR, Spindler KP. Ipsilateral graft and contralateral ACL rupture at five years or more following ACL reconstruction: A systematic review. J Bone Joint Surg Am 93: 1159–1165, 2011.