The purpose of this study was to compare the kinematics of assisted and unassisted plyometric training of vertical jumping and rebounding activities following a six-week training intervention. 13 youth males from a professional football academy completed six weeks of either unassisted (n = 6) or band-assisted (n = 7) plyometric training sessions twice a week during their competitive season. Pre- and post-assessments of counter-movement jump (CMJ) height, 50 cm drop-jump (DJ50) ground contact time (GCT), jump height and reactive strength index (RSI), and submaximal-hopping (SMH) GCT, jump height and RSI were compared. Pre- and post-assessment ankle angle at touch-down (TD), peak flexion (PF) and mid-flight (MF) were also analysed for the submaximal-hop test only. Following training, significant main effects of time were observed for CMJ height, DJ50 GCT and MF ankle angle (p < 0.05) and a significant effect of group was observed for DJ50 RSI (p < 0.05). These results suggest that both unassisted and assisted plyometric training may be useful for enhancing the kinematics and technical performance of plyometric activities in a youth male football population.


Assisted plyometric training, Unassisted plyometric training, Youth football, Kinematics,


  1. G. Markovic and P. Mikulic, Neuro-musculoskeletal and performance adaptations to lower-extremity plyometric training, Sports Medicine, 40 (2010) 859-895.https://doi.org/10.2165/11318370-000000000-00000
  2. M.S. Chelly, M.A. Ghenem, K. Abid, S. Hermassi, Z. Tabka, R.J. Shephard, Effects of in-season short-term plyometric training program on leg power, jump-and sprint performance of soccer players, Journal of Strength and Conditioning Research, 24 (2010) 2670-2676.https://doi.org/10.1519/jsc.0b013e3181e2728f
  3. R. Ramírez-Campillo, F. Gallardo, C. Henriquez-Olguín, C.M.P. Meylan, C. Martínez, C. Álvarez, A. Caniuqueo, E.L. Cadore, M. Izquierdo, Effect of vertical, horizontal, and combined plyometric training on explosive, balance, and endurance performance of young soccer players, Journal of Strength and Conditioning Research, 29 (2015) 1784-1795. https://doi.org/10.1519/jsc.0000000000000827
  4. R. Ramírez-Campillo, C. Henríquez-Olguín, C. Burgos, D.C. Andrade, D. Zapata, C. Martínez, C. Álvarez, E.I. Baez, M. Castro-Sepúlveda, L. Peñailillo, M. Izquierdo, Effect of progressive volume-based overload during plyometric training on explosive and endurance performance in young soccer players, Journal of Strength and Conditioning Research, 29 (2015) 1884-1893. https://doi.org/10.1519/jsc.0000000000000836
  5. R. Ramírez-Campillo, C. Meylan, C. Álvarez, C. Henríquez-Olguín, C. Martínez, R. Cañas-Jamett, D.C. Andrade, M. Izquierdo, Effects of in-season low-volume high-intensity plyometric training on explosive actions and endurance of young soccer players, Journal of Strength and Conditioning Research, 28 (2014) 1335-1342.https://doi.org/10.1519/jsc.0000000000000284
  6. K. Thomas, D. French and P.R. Hayes, The effect of two plyometric training techniques on muscular power and agility in youth soccer players, Journal of Strength and Conditioning Research, 23 (2009) 332-335. https://doi.org/10.1519/jsc.0b013e318183a01a
  7. K. Khodaei, A. Mohammadi, and N. Badri, A comparison of assisted, resisted, and common plyometric training modes to enhance sprint and agility performance, Journal of Sports Medicine and Physical Fitness, 57 (2017) 1237-1244. https://doi.org/10.23736/s0022-4707.17.06901-8
  8. T.E. Hewett, T.N. Lindenfeld, J.V. Riccobene, F.R. Noyes, The effect of neuromuscular training on the incidence of knee injury in female athletes, American Journal of Sports Medicine, 27 (1999) 699-706. https://doi.org/10.1177/03635465990270060301
  9. O. Faude, T. Koch and T. Meyer, Straight sprinting is the most frequent action in goal situations in professional football, Journal of Sports Sciences, 30 (2012) 625-631. https://doi.org/10.1080/02640414.2012.665940
  10. Ramirez-Campillo R, Alvarez C, Sanchez-Sanchez J, M. Slimani, P. Gentil, M. Souhaiel Chelly, R.J. Shephard, Effects of plyometric jump training on the physical fitness of young male soccer players: Modulation of response by inter-set recovery interval and maturation status, Journal of Sports Sciences, 37 (2019) 2645-2652. https://doi.org/10.1080/02640414.2019.1626049
  11. A. Asadi, R. Ramirez-Campillo, H. Arazi, E. Sáez de Villarreal, The effects of maturation on jumping ability and sprint adaptations to plyometric training in youth soccer players, Journal of Sports Sciences, 36 (2018) 2405-2411. https://doi.org/10.1080/02640414.2018.1459151
  12. R.S. Lloyd, J.M. Radnor, M.B.A.D.S. Croix, J.B. Cronin, J.L. Oliver, Changes in sprint and jump performances after traditional, plyometric, and combined resistance training in male youth pre-and post-peak height velocity, Journal of Strength and Conditioning Research, 30 (2016) 1239-1247. https://doi.org/10.1519/jsc.0000000000001216
  13. McKinlay BJ, Wallace P, Dotan R, D. Long, C. Tokuno, D.A. Gabriel, B. Falk, Effects of plyometric and resistance training on muscle strength, explosiveness, and neuromuscular function in young adolescent soccer players, Journal of Strength and Conditioning Research, 32 (2018) 3039-3050. https://doi.org/10.1519/jsc.0000000000002428
  14. J.M. Wilson and E.P. Flanagan, The role of elastic energy in activities with high force and power requirements: a brief review, Journal of Strength and Conditioning Research, 22 (2008) 1705-1715. https://doi.org/10.1519/jsc.0b013e31817ae4a7
  15. A.V. Hill, The heat of shortening and the dynamic constants of muscle, Proceedings of the Royal Society of London. Series B, 126 (1938) 136-195. https://doi.org/10.1098/rspb.1938.0050
  16. J.M. McBride, G.O. McCaulley and P. Cormie, Influence of preactivity and eccentric muscle activity on concentric performance during vertical jumping, Journal of Strength and Conditioning Research, 22 (2008) 750-757. https://doi.org/10.1519/jsc.0b013e31816a83ef
  17. Van Ingen Schenau GJ, Bobbert MF and De Haan A. Mechanics and energetics of the stretch-shortening cycle: a stimulating discussion, Journal of Applied Biomechanics, 13 (1997) 484-496. https://doi.org/10.1123/jab.13.4.484
  18. T. Finni, S. Ikegaw, V. Lepola, P. Komi, In vivo behavior of vastus lateralis muscle during dynamic performances, European Journal of Sport Science, 1 (2001) 1-13. https://doi.org/10.1080/17461390100071101
  19. A. Arampatzis, F. Schade, M. Walsh, G.P. Brüggemann, Influence of leg stiffness and its effect on myodynamic jumping performance, Journal of Electromyography & Kinesiology, 11 (2001) 355-364. https://doi.org/10.1016/s1050-6411(01)00009-8
  20. C.T. Farley, H.H. Houdijk, C. V. Strien, M. Louie, Mechanism of leg stiffness adjustment for hopping on surfaces of different stiffnesses, Journal of Applied Physiology, 85 (1998) 1044-1055. https://doi.org/10.1152/jappl.1998.85.3.1044
  21. C.T. Farley and D.C. Morgenroth, Leg stiffness primarily depends on ankle stiffness during human hopping, Journal of Biomechanics, 32 (1999) 267-273. https://doi.org/10.1016/s0021-9290(98)00170-5
  22. A.N. Turner and I. Jeffreys, The stretch-shortening cycle: proposed mechanisms and methods for enhancement, Strength & Conditioning Journal, 32 (2010) 87-99. https://doi.org/10.1519/SSC.0b013e3181e928f9
  23. H. Kyröläinen, P.V. Komi and A. Belli, Changes in muscle activity patterns and kinetics with increasing running speed, Journal of Strength and Conditioning Research, 13 (1999) 400-406. https://doi.org/10.1080/02640410400021575
  24. H. Hobara, K. Kanosue and S. Suzuki, Changes in muscle activity with increase in leg stiffness during hopping, Neuroscience Letters, 418 (2007) 55-59. https://doi.org/10.1016/j.neulet.2007.02.064
  25. D.F. Cappa and D.G. Behm, Neuromuscular characteristics of drop and hurdle jumps with different types of landings, Journal of Strength and Conditioning Research, 27 (2013) 3011-3020. https://doi.org/10.1519/jsc.0b013e31828c28b3
  26. T. Muraoka, T. Muramatsu, T. Fukunaga, H. Kanehisa, Influence of tendon slack on electromechanical delay in the human medial gastrocnemius in vivo, Journal of Applied Physiology, 96 (2004) 540-544. https://doi.org/10.1152/japplphysiol.01015.2002
  27. R. Clarke, J. Hughes, R. Aspe, D. Sargent, P. Mundy, Plyometric technical models: biomechanical principles, Professional Strength & Conditioning, 49 (2018) 13-20.
  28. P.M. Fitts and M.I. Posner, Human Performance. Belmont, CA: Brooks/Cole, 1967.
  29. R. Gray, Attending to the execution of a complex sensorimotor skill: expertise differences, choking, and slumps, Journal of Experimental Psychology: Applied, 10 (2004) 42-54. https://doi.org/10.1037/1076-898x.10.1.42
  30. Tran TT, Brown LE, Coburn JW, S.K. Lynn, N.C. Dabbs, Effects of assisted jumping on vertical jump parameters, Current Sports Medicine Reports, 11 (2012) 155-159. https://doi.org/10.1249/jsr.0b013e31825640bb
  31. O.A. Donoghue, H. Shimojo and H. Takagi, Impact forces of plyometric exercises performed on land and in water, Sports Health 3 (2011) 303-309. https://dx.doi.org/10.1177%2F1941738111403872
  32. A.L. Ross and J.L. Hudson, Efficacy of a mini-trampoline program for improving the vertical jump, 15 International Symposium on Biomechanics in Sports (1997) 63-69.
  33. A.R. Elias, C.D. Hammill and R.L. Mizner, The effect of body weight support on kinetics and kinematics of a repetitive plyometric task, Journal of Applied Biomechanics, 32 (2016) 69-77. https://doi.org/10.1123/jab.2015-0077
  34. V.L. Cazas, L.E. Brown, J.W. Coburn, A.J. Galpin, J.J. Tufano, J.W. Laporta, A.M. Du Bois, Influence of rest intervals after assisted jumping on bodyweight vertical jump performance, Journal of Strength and Conditioning Research, 27 (2013) 64-68. https://doi.org/10.1519/jsc.0b013e3182772f13
  35. J.M. Sheppard, A.A. Dingley, I. Janssen, W.Spratford, D.W. Chapman, R.U. Newton, The effect of assisted jumping on vertical jump height in high-performance volleyball players, Journal of Science and Medicine in Sport, 14 (2011) 85-89. https://doi.org/10.1016/j.jsams.2010.07.006
  36. H. Makaruk, J.B. Winchester, A. Czaplicki, T. Sacewicz, J. Zieliński, J. Sadowski Effects of assisted and traditional drop jumps on jumping performance, International Journal of Sports Science & Coaching, 9 (2014) 1217-1225. https://doi.org/10.1260%2F1747-9541.9.5.1217
  37. T.T. Tran, L.E. Brown, J.W. Coburn, S.K. Lynn, N.C. Dabbs, M.K. Schick, E.E. Schick, A.V. Khamoui, B.P. Uribe, G.J. Noffal, Effects of different elastic cord assistance levels on vertical jump, Journal of Strength and Conditioning Research, 25 (2011) 3472-3478. https://doi.org/10.1519/jsc.0b013e318217664c
  38. C.K. Argus, N.D. Gill, J.W. Keogh, A.J. Blazevich, W.G. Hopkins, Kinetic and training comparisons between assisted, resisted, and free countermovement jumps, Journal of Strength and Conditioning Research, 25 (2011) 2219-2227. https://doi.org/10.1519/jsc.0b013e3181f6b0f4
  39. D.H. Potach and D.A. Chu, Plyometric Training. In: Beachle TR and Earle RW (eds) Essentials of strength training and conditioning, 3rd ed. Champaign, IL: Human Kinetics, 2008, pp.413-456.
  40. J.J. Tufano, J. Malecek, M. Steffl, P. Stastny, V. Hojka, T. Vetrovsky, Field-based and lab-based assisted jumping: unveiling the testing and training implications, Frontiers in Physiology, 9 (2018) 1284. https://doi.org/10.3389/fphys.2018.01284
  41. G. Wulf, Attentional focus and motor learning: a review of 15 years, International Review of Sport and Exercise Psychology, 6 (2013) 77-104. http://dx.doi.org/10.1080/1750984X.2012.723728
  42. S. Chavda, T. Bromley, P. Jarvis, S. Williams, C. Bishop, A. Turner, J. Lake, P. Mundy, Force-time characteristics of the countermovement jump: analyzing the curve in excel, Strength & Conditioning Journal, 40 (2018) 67-77. https://doi.org/10.1519/SSC.0000000000000353
  43. N.A.H. Hisham, A.F.A. Nazri, J. Madete, L. Herawati, J. Mahmud, Measuring ankle angle and analysis of walking gait using kinovea. In: International Medical Device and Technology Conference, Johur, Malyasia, 2017.
  44. G. Markovic, S. Vuk and S. Jaric, Effects of jump training with negative versus positive loading on jumping mechanics, International Journal of Sports Medicine, 32 (2011) 365-372. https://doi.org/10.1055/s-0031-1271678
  45. J.M. Radnor, J.L. Oliver, C.M. Waugh, G.D. Myer, I.S. Moore, R.S. Lloyd, The influence of growth and maturation on stretch-shortening cycle function in youth, Sports Medicine, 48 (2018) 57-71. https://doi.org/10.1007/s40279-017-0785-0
  46. K. Kubo, M. Morimoto, T. Komuro, H. Yata, N. Tsunoda, H. Kanehisa, T. Fukunaga, Effects of plyometric and weight training on muscle-tendon complex and jump performance, Medicine & Science in Sports & Exercise, 39 (2007) 1801-1810. https://doi.org/10.1249/mss.0b013e31813e630a
  47. S. Khuu, L.L. Musalem, T.A. Beach, Verbal instructions acutely affect drop vertical jump biomechanics—implications for athletic performance and injury risk assessments, Journal of Strength and Conditioning Research, 29 (2015) 2816-2826. https://doi.org/10.1519/jsc.0000000000000938
  48. J.S. Pedley, R.S. Lloyd, P. Read, M. Isabel, J.L. Oliver, Drop jump: a technical model for scientific application, Strength & Conditioning Journal, 39 (2017) 36-44. https://doi.org/10.1519/SSC.0000000000000331
  49. R.S. Lloyd, J.L. Oliver, M.G. Hughes, C.A. Williams, The effects of 4-weeks of plyometric training on reactive strength index and leg stiffness in male youths, Journal of Strength and Conditioning Research, 26 (2012) 2812-2819. https://doi.org/10.1519/jsc.0b013e318242d2ec
  50. E.S.S. De Villarreal, E. Kellis, W.J. Kraemer, M. Izquierdo, Determining variables of plyometric training for improving vertical jump height performance: a meta-analysis, Journal of Strength and Conditioning Research, 23 (2009) 495-506. https://doi.org/10.1519/jsc.0b013e318196b7c6
  51. C. Leukel, W. Taube, M. Gruber, M. Hodapp, A. Gollhofer, Influence of falling height on the excitability of the soleus H-reflex during drop jumps, Acta Physiologica, 192 (2008) 569-576. https://doi.org/10.1111/j.1748-1716.2007.01762.x