Is a Bimodal Force-Time Curve Related to Countermovement Jump Performance?

Rodney Kennedy, David Drake

Research output: Contribution to journalArticle

Abstract

A countermovement jump (CMJ) represents one of the most frequently used performance tests for monitoring neuromuscular function in athletes. An often-overlooked feature that may provide some useful diagnostic information is the actual shape of the force-time curve. The aim of this study was therefore to consider how the shape of the force-time curve influences jump performance. Thirty-three male rugby union players performed two CMJs on a force plate, with discrete variables and continuous curve analysis used. The subjects were dichotomized based on shape of the force-time curve during the propulsion phase and by jump height. The differences between the unimodal and bimodal groups were unclear for jump height (ES = 0.28, ±0.58) and reactive strength index-modified (ES = −0.30, ±0.59). A substantial difference between high (40.2 ± 2.9 cm) and low (31.2 ± 3.2 cm) jumpers only existed in the late propulsion phase by 79.0% to 97.0% of the normalized force-time curve. A bimodal force-time curve is not representative of an optimal pattern of performance and simply reflects an inefficient stretch-shortening cycle. The inter-individual variability that exists in braking COM displacement renders temporal phase analysis impractical in cross-sectional type studies.
LanguageEnglish
JournalSports
Volume6
Issue number2 (36)
DOIs
Publication statusPublished - 18 Apr 2018

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Neuromuscular Monitoring
Football
Athletes
Cross-Sectional Studies

Keywords

  • movement
  • attention
  • neuromuscular function
  • shape

Cite this

@article{1871b2a0b48b4720891c9323f99436e0,
title = "Is a Bimodal Force-Time Curve Related to Countermovement Jump Performance?",
abstract = "A countermovement jump (CMJ) represents one of the most frequently used performance tests for monitoring neuromuscular function in athletes. An often-overlooked feature that may provide some useful diagnostic information is the actual shape of the force-time curve. The aim of this study was therefore to consider how the shape of the force-time curve influences jump performance. Thirty-three male rugby union players performed two CMJs on a force plate, with discrete variables and continuous curve analysis used. The subjects were dichotomized based on shape of the force-time curve during the propulsion phase and by jump height. The differences between the unimodal and bimodal groups were unclear for jump height (ES = 0.28, ±0.58) and reactive strength index-modified (ES = −0.30, ±0.59). A substantial difference between high (40.2 ± 2.9 cm) and low (31.2 ± 3.2 cm) jumpers only existed in the late propulsion phase by 79.0{\%} to 97.0{\%} of the normalized force-time curve. A bimodal force-time curve is not representative of an optimal pattern of performance and simply reflects an inefficient stretch-shortening cycle. The inter-individual variability that exists in braking COM displacement renders temporal phase analysis impractical in cross-sectional type studies.",
keywords = "movement, attention, neuromuscular function, shape",
author = "Rodney Kennedy and David Drake",
note = "Reference text: 1. Mandic, R.; Jakovljevic, S.; Jaric, S. Effects of countermovement depth on kinematic and kinetic patterns of maximum vertical jumps. J. Electromyogr. Kinesiol. 2015, 25, 265–272, doi:10.1016/j.jelekin.2014.11.001. 2. Silva, J.R.; Rumpf, M.C.; Hertzog, M.; Castagna, C.; Farooq, A.; Girard, O.; Hader, K. Acute and residual soccer match-related fatigue: A systematic review and meta-analysis. Sports Med. 2017, 1–45, doi:10.1007/s40279-017-0798-8. 3. Claudino, J.G.; Cronin, J.; Mez{\^e}ncio, B.; McMaster, D.T.; McGuigan, M.; Tricoli, V.; Amadio, A.C.; Serr{\~a}o, J.C. The countermovement jump to monitor neuromuscular status: A meta-analysis. J. Sci. Med. Sport 2017, 20, 397–402, doi:10.1016/j.jsams.2016.08.011. 4. Rowell, A.E.; Aughey, R.J.; Hopkins, W.G.; Stewart, A.M.; Cormack, S.J. Identification of sensitive measures of recovery following external load from football match play. Int. J. Sports Physiol. Perform. 2017, 1–44, doi:10.1123/ijspp.2015-0012. 5. Cormie, P.; McGuigan, M.R.; Newton, R.U. Adaptations in athletic performance after ballistic power versus strength training. Med. Sci. Sports Exerc. 2010, 42, 1582–1598, doi:10.1249/MSS.0b013e3181d2013a. 6. Adamson, G.T.; Whitney, R.J. Critical appraisal of jumping as a measure of human power. Med. Sport 1971, 6, 208–211. 7. Sole, C.J.; Mizuguchi, S.; Sato, K.; Moir, G.L.; Stone, M.H. Phase characteristics of the countermovement jump force-time curve: A comparison of athletes by jumping ability. J. Strength Cond. Res. 2018, 32, 1155–1165, doi:10.1519/JSC.0000000000001945. 8. Garhammer, J.; Gregor, R. Propulsion forces as a function of intensity for weightlifting and vertical jumping. J. Appl. Sport Sci. Res. 1992, 6, 129–134. 9. Dowling, J.J.; Vamos, L. Identification of kinetic and temporal factors related to vertical jump performance. J. Appl. Biomech. 1993, 9, 95–110, doi:10.1123/jab.9.2.95. 10. Payne, A.H.; Slater, W.J.; Telford, T. The use of a force platform in the study of athletic activities. A preliminary investigation. Ergonomics 1968, 11, 123–143, doi:10.1080/00140136808930950. 11. Miller, D. A biomechanical analysis of the contribution of the trunk to standing vertical jump take-offs. In Physical Education, Sports and Sciences; Broekhov, J., Ed.; Microform Publications: Eugene, OR, USA, 1976; pp. 355–374. 12. Kurz, G.; Stockinger, C.; Richter, A.; Potthast, W. Is the local minimum in the force time history in countermovement jumps related to jump performance. Portugese J. Sport Sci. 2011, 11 (Suppl. 2), 1009–1010. 13. McMaster, D.T. A comparison unimodal and bimodal countermovement jump force-time curves. In Proceedings of the Sport and Exercise Science New Zealand Conference, Cambridge, New Zealand, 28–29 October 2016. 14. Cormie, P.; McBride, J.M.; McCauley, G.O. Power-time, force-time, and velocity-time curve analysis of the countermovement jump: Impact of training. J. Strength Cond. Res. 2009, 23, 177–186. 15. Miller, D.I.; East, D.J. Kinematic and kinetic correlates of vertical jumping in women. In Biomechanics V-B; University Park Press: Baltimore, MD, USA, 1976; pp. 65–72. 16. Smith, A.J. A Study of the Forces on the Body in Athletic Activities with Particular Reference to Jumping. Ph.D. Thesis, University of Leeds, Leeds, UK, 1972. 17. Helwig, N.E.; Hong, S.; Hsiao-Wecksler, E.T.; Polk, J.D. Methods to temporally align gait cycle data. J. Biomech. 2011, 44, 561–566, doi:10.1016/j.jbiomech.2010.09.015. 18. Flor{\'i}a, P.; G{\'o}mez-Landero, L.A.; Su{\'a}rez-Arrones, L.; Harrison, A.J. Kinetic and kinematic analysis for assessing the differences in countermovement jump performance in rugby players. J. Strength Cond. Res. 2016, 30, 2533–2539, doi:10.1519/JSC.0000000000000502. 19. Cormie, P.; McGuigan, M.R.; Newton, R.U. Influence of strength on magnitude and mechanisms of adaptation to power training. Med. Sci. Sports Exerc. 2010, 42, 1566–1581, doi:10.1249/MSS.0b013e3181cf818d. 20. McMahon, J.J.; Murphy, S.; Rej, S.J.E.; Comfort, P. Countermovement jump phase characteristics of senior and academy rugby league players. Int. J. Sports Physiol. Perform. 2016, 1–23, doi:10.1123/ijspp.2016-0467. 21. McBride, J.M.; Snyder, J.G. Mechanical efficiency and Force-time curve variation during repetitive jumping in trained and untrained jumpers. Eur. J. Appl. Physiol. 2012, 112, 3469–3477, doi:10.1007/s00421-012-2327-7. 22. Rice, P.E.; Goodman, C.L.; Capps, C.R.; Triplett, N.T.; Erickson, T.M.; McBride, J.M. Force- and power-time curve comparison during jumping between strength-matched male and female basketball players. Eur. J. Sport Sci. 2016, 1391, 1–8, doi:10.1080/17461391.2016.1236840. 23. Batterham, A.M.; Hopkins, W.G. Making meaningful inferences about magnitudes. Int. J. Sport Physiol. Perform. 2006, 1, 50–57. 24. Street, C.; McMillan, S.; Board, W.; Rasmussen, M.; Heneghan, J.M. Sources of error in determining countermovement jump height with the impulse method. J. Appl. Biomech. 2001, 17, 43–54, doi:10.1123/jab.17.1.43. 25. McMahon, J.J.; Jones, P.A.; Dos’Santos, T.; Comfort, P. Influence of dynamic strength index on countermovement jump force-, power-, velocity-, and displacement-time curves. Sports 2017, 5, 72, doi:10.3390/sports5040072. 26. Feltner, M.E.; Fraschetti, D.J.; Crisp, R.J. Upper extremity augmentation of lower extremity kinetics during countermovement vertical jumps. J. Sports Sci. 1999, 17, 449–466, doi:10.1080/026404199365768. 27. Ebben, W.P.; Petushek, E.J. Using the reactive strength index modified to evaluate plyometric performance. J. Strength Cond. Res. 2010, 24, 1983–1987, doi:10.1519/JSC.0b013e3181e72466. 28. Cormie, P.; Cormie, P.; McBride, J.M.; McCaulley, G.O. Power time, force time, and velocity time curve analysis during the jump squat: Impact of load. J. Appl. Biomech. 2008, 24, 112–120. 29. Hopkins, W.G. A spreadsheet for analysis of straightforward controlled trials. Sportscience 2003, 7, 1–8, doi:10.1119/1.14219. 30. Hopkins, W.G.; Marshall, S.W.; Batterham, A.M.; Hanin, J. Progressive statistics for studies in sports medicine and exercise science. Med. Sci. Sports Exerc. 2009, 41, 3–12, doi:10.1249/MSS.0b013e31818cb278. 31. Castagna, C.; Iellamo, F.; Impellizzeri, F.M.; Manzi, V. Validity and reliability of the 45-15 test for aerobic fitness in young soccer players. Int. J. Sport. Physiol. Perform. 2014, 9, 525–531, doi:10.1519/JSC.0000000000000534. 32. Lockie, R.G.; Schultz, A.B.; Callaghan, S.J.; Jeffriess, M.D. The effects of isokinetic knee extensor and flexor strength on dynamic stability as measured by functional reaching. Isokinet. Exerc. Sci. 2013, 21, 301–309, doi:10.3233/IES-130501. 33. Hopkins, W.G. How to interpret changes in an athletic performance test. Sportscience 2004, 8, 1–7, doi:10.1097/00005768-199804000-00026. 34. Mandic, R.; Knezevic, O.M.; Mirkov, D.M.; Jaric, S. Control strategy of maximum vertical jumps: The preferred countermovement depth may not be fully optimized for jump height. J. Hum. Kinet. 2016, 52, 85–94, doi:10.1515/hukin-2015-0196. 35. Balster, W.; Er Lim, C.X.; Kong, P.W. Effects of a deeper countermovement on vertical jump biomechanics after three weeks of familiarisation—Preliminary findings. Int. J. Hum. Mov. Sports Sci. 2016, 4, 51–60, doi:10.13189/saj.2016.040401. 36. Gheller, R.G.; Dal Pupo, J.; Ache-Dias, J.; Detanico, D.; Padulo, J.; dos Santos, S.G. Effect of different knee starting angles on intersegmental coordination and performance in vertical jumps. Hum. Mov. Sci. 2015, 42, 71–80, doi:10.1016/j.humov.2015.04.010. 37. Kirby, T.J.; McBride, J.M.; Haines, T.L.; Dayne, A.M. Relative net vertical impulse determines jumping performance. J. Appl. Biomech. 2011, 27, 207–214. 38. Salles, A.S.; Baltzopoulos, V.; Rittweger, J. Differential effects of countermovement magnitude and volitional effort on vertical jumping. Eur. J. Appl. Physiol. 2011, 111, 441–448, doi:10.1007/s00421-010-1665-6. 39. Markovic, S.; Mirkov, D.M.; Nedeljkovic, A.; Jaric, S. Body size and countermovement depth confound relationship between muscle power output and jumping performance. Hum. Mov. Sci. 2014, 33, 203–210, doi:10.1016/j.humov.2013.11.004. 40. Bobbert, M.F. Why is the force-velocity relationship in leg press tasks quasi-linear rather than hyperbolic? J. Appl. Physiol. 2012, 112, 1975–1983, doi:10.1152/japplphysiol.00787.2011. 41. Winter, E.M.; Abt, G.; Brookes, F.B.C.; Challis, J.H.; Fowler, N.E.; Knudson, D.V.; Knuttgen, H.G.; Kraemer, W.J.; Lane, A.M.; van Mechelen, W.; et al. Misuse of “power” and other mechanical terms in sport and exercise science research. J. Strength Cond. Res. 2016, 30, 292–300, doi:10.1519/JSC.0000000000001101. 42. McMahon, J.J.; Jones, P.A.; Suchomel, T.J.; Lake, J.; Comfort, P. Influence of Reactive Strength Index Modified on Force- and Power-Time Curves. Int. J. Sports Physiol. Perform. 2017, 1–24, doi:10.1123/ijspp.2017-0056. 43. Papaiakovou, G. Kinematic and kinetic differences in the execution of vertical jumps between people with good and poor ankle joint dorsiflexion. J. Sports Sci. 2013, 31, 1789–1796, doi:10.1080/02640414.2013.803587. 44. Brady, C.; Comyns, T.; Harrison, A.; Warrington, G. Focus of attention for diagnostic testing of the force-velocity curve. Strength Cond. J. 2017, 39, 57–70, doi:10.1519/SSC.0000000000000271. 45. McMahon, J.; Rej, S.; Comfort, P. Sex Differences in Countermovement Jump Phase Characteristics. Sports 2017, 5, 8, doi:10.3390/sports5010008.",
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Is a Bimodal Force-Time Curve Related to Countermovement Jump Performance? / Kennedy, Rodney; Drake, David.

Vol. 6, No. 2 (36), 18.04.2018.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Is a Bimodal Force-Time Curve Related to Countermovement Jump Performance?

AU - Kennedy, Rodney

AU - Drake, David

N1 - Reference text: 1. Mandic, R.; Jakovljevic, S.; Jaric, S. Effects of countermovement depth on kinematic and kinetic patterns of maximum vertical jumps. J. Electromyogr. Kinesiol. 2015, 25, 265–272, doi:10.1016/j.jelekin.2014.11.001. 2. Silva, J.R.; Rumpf, M.C.; Hertzog, M.; Castagna, C.; Farooq, A.; Girard, O.; Hader, K. Acute and residual soccer match-related fatigue: A systematic review and meta-analysis. Sports Med. 2017, 1–45, doi:10.1007/s40279-017-0798-8. 3. Claudino, J.G.; Cronin, J.; Mezêncio, B.; McMaster, D.T.; McGuigan, M.; Tricoli, V.; Amadio, A.C.; Serrão, J.C. The countermovement jump to monitor neuromuscular status: A meta-analysis. J. Sci. Med. Sport 2017, 20, 397–402, doi:10.1016/j.jsams.2016.08.011. 4. Rowell, A.E.; Aughey, R.J.; Hopkins, W.G.; Stewart, A.M.; Cormack, S.J. Identification of sensitive measures of recovery following external load from football match play. Int. J. Sports Physiol. Perform. 2017, 1–44, doi:10.1123/ijspp.2015-0012. 5. Cormie, P.; McGuigan, M.R.; Newton, R.U. Adaptations in athletic performance after ballistic power versus strength training. Med. Sci. Sports Exerc. 2010, 42, 1582–1598, doi:10.1249/MSS.0b013e3181d2013a. 6. Adamson, G.T.; Whitney, R.J. Critical appraisal of jumping as a measure of human power. Med. Sport 1971, 6, 208–211. 7. Sole, C.J.; Mizuguchi, S.; Sato, K.; Moir, G.L.; Stone, M.H. Phase characteristics of the countermovement jump force-time curve: A comparison of athletes by jumping ability. J. Strength Cond. Res. 2018, 32, 1155–1165, doi:10.1519/JSC.0000000000001945. 8. Garhammer, J.; Gregor, R. Propulsion forces as a function of intensity for weightlifting and vertical jumping. J. Appl. Sport Sci. Res. 1992, 6, 129–134. 9. Dowling, J.J.; Vamos, L. Identification of kinetic and temporal factors related to vertical jump performance. J. Appl. Biomech. 1993, 9, 95–110, doi:10.1123/jab.9.2.95. 10. Payne, A.H.; Slater, W.J.; Telford, T. The use of a force platform in the study of athletic activities. A preliminary investigation. Ergonomics 1968, 11, 123–143, doi:10.1080/00140136808930950. 11. Miller, D. A biomechanical analysis of the contribution of the trunk to standing vertical jump take-offs. In Physical Education, Sports and Sciences; Broekhov, J., Ed.; Microform Publications: Eugene, OR, USA, 1976; pp. 355–374. 12. Kurz, G.; Stockinger, C.; Richter, A.; Potthast, W. Is the local minimum in the force time history in countermovement jumps related to jump performance. Portugese J. Sport Sci. 2011, 11 (Suppl. 2), 1009–1010. 13. McMaster, D.T. A comparison unimodal and bimodal countermovement jump force-time curves. In Proceedings of the Sport and Exercise Science New Zealand Conference, Cambridge, New Zealand, 28–29 October 2016. 14. Cormie, P.; McBride, J.M.; McCauley, G.O. Power-time, force-time, and velocity-time curve analysis of the countermovement jump: Impact of training. J. Strength Cond. Res. 2009, 23, 177–186. 15. Miller, D.I.; East, D.J. Kinematic and kinetic correlates of vertical jumping in women. In Biomechanics V-B; University Park Press: Baltimore, MD, USA, 1976; pp. 65–72. 16. Smith, A.J. A Study of the Forces on the Body in Athletic Activities with Particular Reference to Jumping. Ph.D. Thesis, University of Leeds, Leeds, UK, 1972. 17. Helwig, N.E.; Hong, S.; Hsiao-Wecksler, E.T.; Polk, J.D. Methods to temporally align gait cycle data. J. Biomech. 2011, 44, 561–566, doi:10.1016/j.jbiomech.2010.09.015. 18. Floría, P.; Gómez-Landero, L.A.; Suárez-Arrones, L.; Harrison, A.J. Kinetic and kinematic analysis for assessing the differences in countermovement jump performance in rugby players. J. Strength Cond. Res. 2016, 30, 2533–2539, doi:10.1519/JSC.0000000000000502. 19. Cormie, P.; McGuigan, M.R.; Newton, R.U. Influence of strength on magnitude and mechanisms of adaptation to power training. Med. Sci. Sports Exerc. 2010, 42, 1566–1581, doi:10.1249/MSS.0b013e3181cf818d. 20. McMahon, J.J.; Murphy, S.; Rej, S.J.E.; Comfort, P. Countermovement jump phase characteristics of senior and academy rugby league players. Int. J. Sports Physiol. Perform. 2016, 1–23, doi:10.1123/ijspp.2016-0467. 21. McBride, J.M.; Snyder, J.G. Mechanical efficiency and Force-time curve variation during repetitive jumping in trained and untrained jumpers. Eur. J. Appl. Physiol. 2012, 112, 3469–3477, doi:10.1007/s00421-012-2327-7. 22. Rice, P.E.; Goodman, C.L.; Capps, C.R.; Triplett, N.T.; Erickson, T.M.; McBride, J.M. Force- and power-time curve comparison during jumping between strength-matched male and female basketball players. Eur. J. Sport Sci. 2016, 1391, 1–8, doi:10.1080/17461391.2016.1236840. 23. Batterham, A.M.; Hopkins, W.G. Making meaningful inferences about magnitudes. Int. J. Sport Physiol. Perform. 2006, 1, 50–57. 24. Street, C.; McMillan, S.; Board, W.; Rasmussen, M.; Heneghan, J.M. Sources of error in determining countermovement jump height with the impulse method. J. Appl. Biomech. 2001, 17, 43–54, doi:10.1123/jab.17.1.43. 25. McMahon, J.J.; Jones, P.A.; Dos’Santos, T.; Comfort, P. Influence of dynamic strength index on countermovement jump force-, power-, velocity-, and displacement-time curves. Sports 2017, 5, 72, doi:10.3390/sports5040072. 26. Feltner, M.E.; Fraschetti, D.J.; Crisp, R.J. Upper extremity augmentation of lower extremity kinetics during countermovement vertical jumps. J. Sports Sci. 1999, 17, 449–466, doi:10.1080/026404199365768. 27. Ebben, W.P.; Petushek, E.J. Using the reactive strength index modified to evaluate plyometric performance. J. Strength Cond. Res. 2010, 24, 1983–1987, doi:10.1519/JSC.0b013e3181e72466. 28. Cormie, P.; Cormie, P.; McBride, J.M.; McCaulley, G.O. Power time, force time, and velocity time curve analysis during the jump squat: Impact of load. J. Appl. Biomech. 2008, 24, 112–120. 29. Hopkins, W.G. A spreadsheet for analysis of straightforward controlled trials. Sportscience 2003, 7, 1–8, doi:10.1119/1.14219. 30. Hopkins, W.G.; Marshall, S.W.; Batterham, A.M.; Hanin, J. Progressive statistics for studies in sports medicine and exercise science. Med. Sci. Sports Exerc. 2009, 41, 3–12, doi:10.1249/MSS.0b013e31818cb278. 31. Castagna, C.; Iellamo, F.; Impellizzeri, F.M.; Manzi, V. Validity and reliability of the 45-15 test for aerobic fitness in young soccer players. Int. J. Sport. Physiol. Perform. 2014, 9, 525–531, doi:10.1519/JSC.0000000000000534. 32. Lockie, R.G.; Schultz, A.B.; Callaghan, S.J.; Jeffriess, M.D. The effects of isokinetic knee extensor and flexor strength on dynamic stability as measured by functional reaching. Isokinet. Exerc. Sci. 2013, 21, 301–309, doi:10.3233/IES-130501. 33. Hopkins, W.G. How to interpret changes in an athletic performance test. Sportscience 2004, 8, 1–7, doi:10.1097/00005768-199804000-00026. 34. Mandic, R.; Knezevic, O.M.; Mirkov, D.M.; Jaric, S. Control strategy of maximum vertical jumps: The preferred countermovement depth may not be fully optimized for jump height. J. Hum. Kinet. 2016, 52, 85–94, doi:10.1515/hukin-2015-0196. 35. Balster, W.; Er Lim, C.X.; Kong, P.W. Effects of a deeper countermovement on vertical jump biomechanics after three weeks of familiarisation—Preliminary findings. Int. J. Hum. Mov. Sports Sci. 2016, 4, 51–60, doi:10.13189/saj.2016.040401. 36. Gheller, R.G.; Dal Pupo, J.; Ache-Dias, J.; Detanico, D.; Padulo, J.; dos Santos, S.G. Effect of different knee starting angles on intersegmental coordination and performance in vertical jumps. Hum. Mov. Sci. 2015, 42, 71–80, doi:10.1016/j.humov.2015.04.010. 37. Kirby, T.J.; McBride, J.M.; Haines, T.L.; Dayne, A.M. Relative net vertical impulse determines jumping performance. J. Appl. Biomech. 2011, 27, 207–214. 38. Salles, A.S.; Baltzopoulos, V.; Rittweger, J. Differential effects of countermovement magnitude and volitional effort on vertical jumping. Eur. J. Appl. Physiol. 2011, 111, 441–448, doi:10.1007/s00421-010-1665-6. 39. Markovic, S.; Mirkov, D.M.; Nedeljkovic, A.; Jaric, S. Body size and countermovement depth confound relationship between muscle power output and jumping performance. Hum. Mov. Sci. 2014, 33, 203–210, doi:10.1016/j.humov.2013.11.004. 40. Bobbert, M.F. Why is the force-velocity relationship in leg press tasks quasi-linear rather than hyperbolic? J. Appl. Physiol. 2012, 112, 1975–1983, doi:10.1152/japplphysiol.00787.2011. 41. Winter, E.M.; Abt, G.; Brookes, F.B.C.; Challis, J.H.; Fowler, N.E.; Knudson, D.V.; Knuttgen, H.G.; Kraemer, W.J.; Lane, A.M.; van Mechelen, W.; et al. Misuse of “power” and other mechanical terms in sport and exercise science research. J. Strength Cond. Res. 2016, 30, 292–300, doi:10.1519/JSC.0000000000001101. 42. McMahon, J.J.; Jones, P.A.; Suchomel, T.J.; Lake, J.; Comfort, P. Influence of Reactive Strength Index Modified on Force- and Power-Time Curves. Int. J. Sports Physiol. Perform. 2017, 1–24, doi:10.1123/ijspp.2017-0056. 43. Papaiakovou, G. Kinematic and kinetic differences in the execution of vertical jumps between people with good and poor ankle joint dorsiflexion. J. Sports Sci. 2013, 31, 1789–1796, doi:10.1080/02640414.2013.803587. 44. Brady, C.; Comyns, T.; Harrison, A.; Warrington, G. Focus of attention for diagnostic testing of the force-velocity curve. Strength Cond. J. 2017, 39, 57–70, doi:10.1519/SSC.0000000000000271. 45. McMahon, J.; Rej, S.; Comfort, P. Sex Differences in Countermovement Jump Phase Characteristics. Sports 2017, 5, 8, doi:10.3390/sports5010008.

PY - 2018/4/18

Y1 - 2018/4/18

N2 - A countermovement jump (CMJ) represents one of the most frequently used performance tests for monitoring neuromuscular function in athletes. An often-overlooked feature that may provide some useful diagnostic information is the actual shape of the force-time curve. The aim of this study was therefore to consider how the shape of the force-time curve influences jump performance. Thirty-three male rugby union players performed two CMJs on a force plate, with discrete variables and continuous curve analysis used. The subjects were dichotomized based on shape of the force-time curve during the propulsion phase and by jump height. The differences between the unimodal and bimodal groups were unclear for jump height (ES = 0.28, ±0.58) and reactive strength index-modified (ES = −0.30, ±0.59). A substantial difference between high (40.2 ± 2.9 cm) and low (31.2 ± 3.2 cm) jumpers only existed in the late propulsion phase by 79.0% to 97.0% of the normalized force-time curve. A bimodal force-time curve is not representative of an optimal pattern of performance and simply reflects an inefficient stretch-shortening cycle. The inter-individual variability that exists in braking COM displacement renders temporal phase analysis impractical in cross-sectional type studies.

AB - A countermovement jump (CMJ) represents one of the most frequently used performance tests for monitoring neuromuscular function in athletes. An often-overlooked feature that may provide some useful diagnostic information is the actual shape of the force-time curve. The aim of this study was therefore to consider how the shape of the force-time curve influences jump performance. Thirty-three male rugby union players performed two CMJs on a force plate, with discrete variables and continuous curve analysis used. The subjects were dichotomized based on shape of the force-time curve during the propulsion phase and by jump height. The differences between the unimodal and bimodal groups were unclear for jump height (ES = 0.28, ±0.58) and reactive strength index-modified (ES = −0.30, ±0.59). A substantial difference between high (40.2 ± 2.9 cm) and low (31.2 ± 3.2 cm) jumpers only existed in the late propulsion phase by 79.0% to 97.0% of the normalized force-time curve. A bimodal force-time curve is not representative of an optimal pattern of performance and simply reflects an inefficient stretch-shortening cycle. The inter-individual variability that exists in braking COM displacement renders temporal phase analysis impractical in cross-sectional type studies.

KW - movement

KW - attention

KW - neuromuscular function

KW - shape

U2 - 10.3390/sports6020036

DO - 10.3390/sports6020036

M3 - Article

VL - 6

IS - 2 (36)

ER -