Original research study The effects of strengthening exercises for wrist flexors and extensors on muscle strength and counter-stroke performance in amateur table tennis players Raoyrin Chanavirut, Ph.D a, b, * , Nontawit Udompanich, BSc a , Phraophimon Udom, BSc a , Ponlapat Yonglitthipagon, PhD a, b , Wanida Donpunha, PhD a , Saowanee Nakmareong, PhD a , Juinichiro Yamauchi, PhD c, d, e a School of Physical Therapy, Faculty of Associated Medical Sciences, Khon Kaen University,123, Mittraphap Highway, Muang District, Khon Kaen, 40002, Thailand b Physical Therapy in Improving Functional Ability Group, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand c Research Center in Back, Neck, Other Joint Pain and Human Performance (BNOJPH), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand d Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo, Japan e Future Institute for Sport Sciences, Tokyo, Japan article info Article history: Received 8 September 2016 Received in revised form 31 January 2017 Accepted 27 February 2017 Keywords: Strengthening exercise Table tennis Hand grip Alternate counter test abstract This study aims to evaluate the effects of strengthening exercises on wrist flexor and extensor strength, hand grip strength, and counter-stroke performance. Thirty amateur table tennis players were recruited and randomly allocated into two groups: the control and the training group (n ¼ 15/group). Pre- and post-data were collected. The training group performed home exercises for six weeks using a bucket filled with water, while the controls were asked to keep their lifestyle as usual. The general character- istics were no significant differences. The training group showed significantly higher levels of wrist flexor and extensor strength than the control group (p < 0.05). However, the difference in hand grip strength was not statistically significant. Both groups showed significant improvement in counter-stroke per- formance (p < 0.05), however, there was no difference between the groups. In conclusion, specific strengthening exercises increase wrist flexor and extensor strength, but they have no effect on either hand grip strength or counter-stroke performance. © 2017 Elsevier Ltd. All rights reserved. 1. Introduction Muscle strength plays a crucial role in determining speed and power in athletic performance. Although an individual's perfor- mance is primarily determined by the specific skills, greater strength leads to a higher potential for athletic performance, especially for untrained individuals. Table tennis is a sport that requires rapid movements, and stroke speed is one of the keys to success (The International Table Tennis Federation Handbook, 2014e2015). Exercises that strengthen wrist muscles can improve the stroke performance of table tennis players by increasing speed and power. A previous study shows hand grip strength is greater in the dominant hand versus the non-dominant hand in young top- level table tennis players (Carrasco et al., 2010). However, another study shows contradicting results in top-level female athletes (Ivanovic and Dopsaj, 2012). These opposite results may suggest the functional complexity of wrist and forearm muscles. A number of studies have been conducted on table tennis players' performance, including stroke performance. However, there are no reports about the effect of wrist-strengthening exercises on hand grip strength and counter-stoke performance. Strengthening exercises for table tennis players should be selected based on the specific movements involved, such as strokes. Therefore, this study aimed to evaluate the effect of strengthening exercises on wrist flexor and extensor * Corresponding author. School of Physical Therapy, Faculty of Associated Medical Sciences, Khon Kaen University, 123, Mittraphap Highway, Muang District, Khon Kaen, 40002, Thailand. E-mail addresses: raocha@kku.ac.th (R. Chanavirut), nuinui_enzo@hotmail.com (N. Udompanich), phraophimon1992@gmail.com (P. Udom), ponlapat@kku.ac.th (P. Yonglitthipagon), wanidadon@kku.ac.th (W. Donpunha), saowna@kku.ac.th (S. Nakmareong), junichiroy@hotmail.com (J. Yamauchi). Contents lists available at ScienceDirect Journal of Bodywork & Movement Therapies journal homepage: www.elsevier.com/jbmt http://dx.doi.org/10.1016/j.jbmt.2017.02.002 1360-8592/© 2017 Elsevier Ltd. All rights reserved. Journal of Bodywork & Movement Therapies xxx (2017) 1e4 Please cite this article in press as: Chanavirut, R., et al., The effects of strengthening exercises for wrist flexors and extensors on muscle strength and counter-stroke performance in amateur table tennis players, Journal of Bodywork & Movement Therapies (2017), http://dx.doi.org/10.1016/ j.jbmt.2017.02.002