Development of a Proprioceptive Neuromuscular Facilitation Stretching System Using a Low-Speed, High-Torque Motor
Keywords:PNF stretching; range of motion; flexibility; hamstrings; low-speed high-torque motor
This study aimed to develop a proprioceptive neuromuscular facilitation (PNF) stretching system using a low-speed, high-torque motor and to investigate the acute response in hip flexion range of motion by applying PNF stretching using this system. The PNF stretching system consisted of a low-speed, high-torque motor with a rotational torque of 157 Nm, a braking torque of 1470 Nm, and a rotational speed of 6 degrees/s, a lever arm attached to the motor and its rotating shaft, and a pedestal mounted on the lever arm. The system, which targets hamstrings, enabled the subjects to raise the leg in a supine straight leg raise position and perform passive muscle lengthening and isometric muscle contractions by operating an electric motor. The study included 21 healthy male students aged between 18 and 21 years. The hold-relax (HR) technique was employed, in which the target muscle was lengthened step by step by performing three 10 s isometric contractions. The hip joint flexion angles were measured at the limit of leg raising without discomfort before and after HR (pre-HR and post-HR) and compared using Wilcoxon signed-rank sum test. The results showed that the hip flexion angle at post-HR (81.4 ± 18.0 degrees) was significantly greater than that at pre-HR (63.9 ± 15.2 degrees) (P < 0.05, effect size = 0.88). In conclusion, the PNF stretching system, which uses a low-speed, high-torque motor, effectively leads to an immediate improvement in hamstring flexibility.
Azuma, A. & Matsui, K. (2021). Prototype of a PNF Stretching System Using a Low-Speed High-Torque Motor. Japanese Journal of Ergonomics, 57(Suppl), 142-143. (in Japanese) https://doi.org/10.5100/jje.57.2D1-5
Borges, M. O., Medeiros, D. M., Minotto, B. B., & Lima, C. S. (2018). Comparison between static stretching and proprioceptive neuromuscular facilitation on hamstring flexibility: systematic review and meta-analysis. European Journal of Physiotherapy, 20(1), 12–19. https://doi.org/10.1080/21679169.2017.1347708
Decoster, L. C., Cleland, J., Alteri, C., & Russell, P. (2005). The effects of hamstrings stretching on range of motion: A systematic literature review. Journal of Orthopaedic and Sports Physical Therapy, 35(6), 377-387. https://www.jospt.org/doi/10.2519/jospt.2005.35.6.377
Ehsan, A., Aslam, J., Gull, M., Rahman, A., Ahmed, S., Anwer, N., Amjad, M. S., & Suleman, H. (2022). Comparison of hold-relax stretching and muscle energy technique on tight hamstring muscle in young adult females. Clinical Practice, 19(4), 1984-1990.
Ekstrand, J., Hagglund, M., & Walden, M. (2011). Epidemiology of muscle injuries in professional football (soccer). American Journal of Sports Medicine, 39, 1226–1232. https://doi.org/10.1177/0363546510395879
Feland, J. B. & Marin, H. N. (2004). Effect of submaximal contraction intensity in contract-relax proprioceptive neuromuscular facilitation stretching. British Journal of Sports Medicine, 38(4), E18. http://dx.doi.org/10.1136/bjsm.2003.010967
Hill, K. J., Robinson, K. P., Cuchna, J. W., & Hoch, M. C. (2017). Immediate effects of proprioceptive neuromuscular facilitation stretching programs compared with passive stretching programs for hamstring flexibility: A critically appraised topic. Journal of Sport Rehabilitation, 26(6), 567–572. https://doi.org/10.1123/jsr.2016-0003
Hindle, K., Whitcomb, T. J., Briggs, W. O., & Hong, J. (2012). Proprioceptive neuromuscular facilitation (PNF): its mechanisms and effects on range of motion and muscular function. Journal of Human Kinetics, 31(1), 105–113. https://doi.org/10.2478/v10078-012-0011-y
Kay, A. D. & Blazevich, A. J. (2009). Isometric contractions reduce plantar flexor moment, Achilles tendon stiffness and neuromuscular activity but remove the subsequent effects of stretch. Journal of Applied Physiology, 107(4), 1181-1189. https://doi.org/10.1152/japplphysiol.00281.2009
Kay, A. D., Husbands-Beasley, J., & Blazevich, A. J. (2015). Effects of contract-relax, static stretching, and isometric contractions on muscle-tendon mechanics. Medicine and Science in Sports and Exercise, 47(10), 2181-2190. doi: 10.1249/MSS.0000000000000632
Konrad, A., Stafilidis, S., & Tilp, M. (2017). Effects of acute static, ballistic, and PNF stretching exercise on the muscle and tendon tissue properties. Scandinavian Journal of Medicine and Science in Sports, 27(10), 1070–1080. https://doi.org/10.1111/sms.12725
Kubo, K., Kanehisa, H., & Fukunaga, T. (2002). Effects of transient muscle contractions and stretching on the tendon structures in vivo. Acta Physiologica Scandinavica, 175(2), 157-164.
Miyahara, Y., Naito, H., & Ogura, Y. (2013). Effects of proprioceptive neuromuscular facilitation stretching and static stretching on maximal voluntary contraction. Journal of Strength and Conditioning Research, 27(1), 195–201. https://doi.org/10.1046/j.1365-201X.2002.00976.x
Puentedura, E. J., Huijbregts, P. A., Celeste, S., Edwards, D., In, A., Landers, M. R., & Fernandez-de-Las-Penas, C. (2011). Immediate effects of quantified hamstring stretching: Hold-relax proprioceptive neuromuscular facilitation versus static stretching. Physical Therapy in Sport, 12(3), 122–126. https://doi.org/10.1016/j.ptsp.2011.02.006
Ruan, M., Li, L., Chen, C., & Wu, X. (2018). Stretch could reduce hamstring injury risk during sprinting by right shifting the length-torque curve. Journal of Strength and Conditioning Research, 32(8), 2190–2198. doi: 10.1519/JSC.0000000000002645
Sbardelotto GAEB, Weisshahn NK, Benincá IL, de Estéfani D, e Lima KMM, & Haupenthal A. Hold-relax PNF is more effective than unilateral lumbar mobilization on increasing hamstring flexibility: A randomized clinical trial. Journal of Bodywork and Movement Therapies, 32: 36-42, 2022. https://doi.org/10.1016/j.jbmt.2022.04.003
Wicke, J., Gainey, K. & Figueroa, M. (2014). A Comparison of self-administered proprioceptive neuromuscular facilitation to static stretching on range of motion and flexibility. Journal of Strength and Conditioning Research, 28(1), 168–172. doi: 10.1519/JSC.0b013e3182956432
Yadav, H. & Lehri, A. (2019). Effects of proprioceptive neuromuscular facilitation on flexibility in males with hamstrings tightness. International Journal of Health Sciences and Research, 9(5), 191-195. Retrieved from: https://www.ijhsr.org/IJHSR_Vol.9_Issue.5_May2019/29.pdf
Yildirim, M. S., Ozyurek, S., Tosun, Oç., Uzer, S., & Gelecek, N. (2016). Comparison of effects of static, proprioceptive neuromuscular facilitation and Mulligan stretching on hip flexion range of motion: a randomized controlled trial. Biology of Sports, 33(1), 89-94. doi: 10.5604/20831862.1194126
Young, W. & Elliott, S. (2001). Acute effects of static stretching, proprioceptive neuromuscular facilitation stretching, and maximum voluntary contractions on explosive force production and jumping performance. Research Quarterly for Exercise and Sport, 72(3), 273–279. https://doi.org/10.1080/02701367.2001.10608960
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.This journal is covered under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/). The rights of printing and reproduction by any way and means are the property of the European Journal of Human Movement, and by extension of each one of the authors of the articles.