Impaired Performance of the Smash Stroke in Badminton Induced by Muscle Fatigue.

PURPOSE: To evaluate the effects of muscle fatigue on badminton performance during a smash stroke. METHODS: In total, 17 young, well-trained players completed 20 forehand smashes twice (prefatigue and postfatigue protocol), and both speed and precision of the strokes were measured. The fatigue protocol consisted of 10 series of 10 maximal countermovement jumps (3-s rest in between) followed by 8 lunges. Perception of effort and countermovement-jump performance during each series were also measured to assess fatigue. RESULTS: Shuttlecock speed decreased moderately (-3.3%) but significantly after the fatigue protocol (P < .001, ηp2=.671). Precision significantly decreased after the fatigue protocol (-10.3%, P = .001, ηp2=.473). The decrease in precision was mainly due to an increased number of faults (P = .006, ηp2=.378, dz = 0.756) and to a decrease in accuracy (P = .066, ηp2=.195, dz = 0.478). CONCLUSION: The present study showed that fatigue impairs performance during specific badminton skills. Moreover, by showing a slight decrease in speed and a large decrease in accuracy of the shuttlecock when fatigue is experienced, the present study suggested that, as previously observed in other racket sports, the speed of the missile appears to be the key factor used by the players to win the rally. Coaches and physical trainers should therefore develop interventions aiming to limit the negative impact of fatigue on badminton strokes.

Is reaction time altered by mental or physical exertion?

PURPOSE: Reaction time, classically divided into premotor time and electromechanical delay (EMD), can be determinant in daily life or sport situations. While some previous studies reported a negative impact of both muscle and mental fatigue on reaction time, the respective contributions of premotor time and EMD to the changes of reaction time remains unclear. The aim of the study was, therefore, to assess the effects of both muscle and mental effort on reaction time and its components. METHODS: Thirteen subjects performed three conditions (mental effort condition, i.e., 14 min of a mathematical cognitive task; muscle effort condition, i.e., intermittent contractions of the biceps brachii; control condition, i.e., watching a documentary). Before and after each condition, reaction time, premotor time and EMD were measured during voluntary contractions of the biceps brachii. EMD was also measured during evoked contractions of the biceps brachii to separate the parts due to the onset of muscle fascicle motion and the onset of force production. RESULTS: Reaction time and premotor time remained stable regardless of the condition considered (all P values > 0.05). EMD increased only after the muscle effort condition (+ 25% during voluntary contractions, no significant; + 17% during evoked contractions, P = 0.001), mainly due to an increase in the passive part of the series elastic component. CONCLUSION: Our study showed that neither mental nor muscle effort has a negative effect on simple reaction time during voluntary contractions.

Mental fatigue alters the speed and the accuracy of the ball in table tennis.

This study aimed at evaluating the effects of mental and muscle fatigue on table tennis performance. Mental fatigue (MF) was induced by completion of 90 minutes of the AX-CPT; muscle fatigue was induced by completion of an eccentric exercise performed with the elbow flexors (biceps fatigue, BF) or the knee extensors (quadriceps fatigue, QF). The control condition consisted of watching a movie. Stroke parameters (speed and accuracy of the ball), as well as feelings of fatigue and force production capacity of the elbow flexors (BF, MF and control conditions) and knee extensors (QF condition), were assessed pre and post fatigue protocols. Feelings of fatigue increased post fatigue protocols. Force production capacity decreased only in the BF and QF conditions. BF and MF induced a decrease in accuracy. This decrease in accuracy was associated with an increased ball speed in the BF condition, and a decreased ball speed in the MF condition. QF had a negligible effect on stroke performance. Our results suggest that both mental fatigue, and muscle fatigue, significantly impair table tennis performance and therefore coaches should take into account both the physical and mental state of table tennis players to optimize performance.

Lower limb muscle activity during table tennis strokes.

This study aimed to compare the muscle activity of lower limbs across typical table tennis strokes. Fourteen high-level players participated in this study in which five typical strokes (backhand top, forehand top, forehand spin, forehand smash, flick) were analysed. Surface electromyography activity (EMG) of eight muscles was recorded (gluteus maximus, biceps femoris, vastus medialis, vastus lateralis, rectus femoris, gastrocnemius medialis, gastrocnemius lateralis, soleus) and normalised to the maximal activity measured during squat jump or isometric maximal voluntary contractions. The forehand spin, the forehand top and the forehand smash exhibited significant higher EMG amplitude when compared with other strokes. Both biceps femoris and gluteus maximus were strongly activated during the smash, forehand spin and forehand top (from 62.8 to 91.7% of maximal EMG activity). Both vastii and rectus femoris were moderately to strongly activated during the forehand spin (from 50.4 to 62.2% of maximal EMG activity) whereas gastrocnemii and soleus exhibited the highest level of activity during the smash (from 67.1 to 92.1% of maximal EMG activity). Our study demonstrates that offensive strokes, such as smash or forehand top, exhibit higher levels of activity than other strokes.

Neuromuscular fatigue and time motion analysis during a table tennis competition.

BACKGROUND: This study aimed to determine the neuromuscular fatigue (central versus peripheral mechanisms) as well as the game characteristics and physical demand induced by a simulated table tennis competition. METHODS: Fourteen national table tennis players participated in this study, in which neuromuscular tests (i.e., maximal voluntary contractions, voluntary activation and twitch properties of the knee extensor muscles) were performed before and immediately after four games of five sets of table tennis to assess both the magnitude of fatigue and its origin. The game characteristics and the physical demand of the players (low-, moderate- and high-intensity actions) were identified using time motion analysis methodology. RESULTS: A significant decrease (-12.5±9.0%) of force was observed at the end of the competition. Voluntary activation significantly decreased at the end of the competition, from 89.4±3.5% to 81.6±7.3%. Electrical and contractile properties were also significantly reduced after the first game (approximately 15% for both the potentiated doublet and M-wave amplitude) and did not decrease thereafter. Moreover, low and moderate actions represented an important portion (84.3±4.7%) of the actions performed by the players, whereas high intensity actions represented 15.7±4.7%. CONCLUSIONS: This study demonstrated that a simulated table tennis competition induced significant fatigue due to central and peripheral alterations. Our study also demonstrated that a large proportion of the actions performed by the players during table tennis can be considered low to moderate intensity actions.

Sensitivity and Reliability of a Specific Test of Stroke Performance in Table Tennis.

PURPOSE: To develop a simple, reliable, and sensitive test to measure stroke performance (ball speed and accuracy) in table tennis. METHODS: Fifty-two players were divided into 3 groups in accordance with their level: expert (EG), advanced (AG), and inexperienced (IG). The test consisted of 45 forehand shots where players were asked to reach 3 targets. The test was performed 2 times (separated by 8 min) during the first session (n = 52) to assess intrasession reliability. A second session (n = 28), at least 3 d later, was performed to test intersession reliability. Both speed and accuracy of the ball were measured to evaluate the absolute sensitivity and reliability of the specific test. RESULTS: This study showed good reliability of the specific test for both ball speed and accuracy of EG and AG (ICC range .42-.96, CV range 2.0-9.0%). However, the reliability is low for IG. Ball speed and accuracy were greater in EG than in the other groups, and both variables were correlated with the level of the players. CONCLUSION: Results suggest that the specific test appears to be a simple and sensitive procedure to assess stroke performance in table tennis and that this test could be a relevant tool for coaches in table tennis.