Effect of exercise induced muscle soreness on the motor control properties of the biceps brachii

The objective of this study was to note the time course changes for up to 28 days on the motor control properties of biceps brachii muscle following a bout of eccentric exercise. Eight subjects (5 male, 25-40 years of age) performed 35 maximal voluntary eccentric contractions with the non-preferred arm of the elbow flexors through 130° of extension of 90°s-1. Voluntary electromyographic (EMG) activity and motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) were recorded via surface electrodes placed over the belly of the biceps brachii muscle. Maximal isometric strength was measured at 90° elbow flexion. A simple elbow flexion/extension tracking task was used to assist visuomotor co-ordination. Subjects displayed greatest strength loss at I day (of control measures) which recovered by 21 days post-exercise. Impairment in the skilled tracking task was noticeable within hours following the exercise, and was greatest 1 day post exercise, but returned to control levels by 3 days. There were no changes in the threshold level of MEP responses to TMS but maximal MEP amplitudes increased on average (although responses were variable). No changes were observed in the EMG activity following exercise. The changes in the motor performance and corticomotor excitability occur following eccentric exercise which may be related to alterations in the pattern of afferent feedback from weakened and/or painful muscles. The implications from this suggest that coaches need to be sympathetic to the needs of the athlete when balancing physical training with skill training/developmen

Corticomotor excitability during precision motor tasks

The aim of this preliminary study was to investigate motor cortex (cortical) excitability between a similar fine visuomotor task of varying difficulty. Ten healthy adults (three female, seven male; 20—45 years of age) participated in the study. Participants were instructed to perform a fine visuomotor task by statically abducting their first index finger against a force transducer which displayed the level of force (represented as a marker) on a computer monitor. This marker was to be maintained between two stationary bars, also displayed on the computer monitor. The level of difficulty was increased by amplifying the position of the marker, making the task more difficult to control. Cortical measures of motor evoked potential (MEP) and silent period (SP) duration in first dorsal interosseous (FDI) muscle were obtained using transcranial magnetic stimulation (TMS) while the participant maintained the ‘‘easy’’ or ‘‘difficult’’ static task. An 11.8% increase in MEP amplitude was observed when subjects undertook the ‘‘difficult’’ task, but no differences in MEP latency or SP duration. The results from this preliminary study suggest that cortical excitability increases reflect the demand required to perform tasks requiring greater precision with suggestions for further research discussed

Understanding, developing and maintaining mental toughness in tennis

Eighteen (10 female and 8 male) recently retired top world-ranked Australian professional tennis players responded to a questionnaire that was developed to address future directions by mental toughness researchers. A series of inductive content analyses was conducted to analyze the qualitative data obtained from participants’ responses. These analyses revealed that mental toughness is a most sought-after dynamic attribute that encompasses a range of abilities (e.g., focus, work ethic) to consistently perform well under pressure. Further, mental toughness is thought to be ‘taught’ and/or ‘acquired’ over many years and can be influenced by factors that include injury, changes in a player’s technique and match results. Examples of mentally tough players were cited and reasons given as to their selection as outstanding mentally tough competitors. Sport psychologists, coaches, parents and other mentors were identified as significant members of a support team to guide and equip players to be mentally tough competitors. This study’s value to the tennis community includes practical benefits from gaining a fuller understanding of what is arguably one of the most important psychological skills in achieving excellence and enjoyment in tennis, namely mental toughness

The dynamic role of elite coach : player and coach perspectives

As part of a larger study on talent development, ten top ranked players and ten coaches (nominated by the player) responded to open-ended questionnaires. Players and coaches were asked them to recall their background in tennis, describe the role of the coach and any changes in this role, and offer suggestions to coaches for nurturing talent. A series of inductive content analyses was conduct to analyze the data. These analyses revealed significant, and changing, roles of the coach during a player’s development to professional status. Recommendations to coaches highlighted the importance of coach philosophy, communication, and planning. Implications for coach education programs are discussed

The influence of parents in identifying and developing Australian female tennis talent

This study investigated the role of parents in developing Australian female professional tennis players. Top WTA ranked Australian singles players (n=10) and their parents (n=10) responded to written questionnaires. Participants were asked to recall their tennisbackground and describe the current role of parents and compare these to possible earlier roles. Further, participants were asked to make recommendations to parents who wanted to help a player develop her talent. A series of inductive content analyses was conducted to analyze the data. These analyses revealed a significant, and changing, role of parents in a development process extending over 10 years. Sacrifices were necessary in order to pursue a tennis career but positive benefits were generally reported by players and their parents. The importance of a caring and respectful home environment for aspiring players was highlighted

Corticomotor responses to attentionally demanding motor performance: a mini-review

Increased attentional demand has been shown to reduce motor performance, leading to increases in accidents, particularly in elderly populations. While these deficits have been well documented behaviorally, their cortical correlates are less well known. Increased attention has been shown to affect activity in prefrontal regions of the cortex. However there have been varying results within past research investigating corticomotor regions, mediating motor performance. This mini-review initially discusses past behavioral research, before moving to studies investigating corticomotor areas in response to changes in attention. Recent dual task studies have revealed a possible decline in the ability of older, but not younger, adults to activate inhibitory processes within the motor cortex, which may be correlated with poor motor performance, and thus accidents. A reduction in cortical inhibition may be caused by neurodegeneration within prefrontal regions of the cortex with age, rendering older adults less able to allocate attention to corticomotor regions

High volume versus low volume balance training on postural sway in adults with previous ankle inversion injury

Balance training is commonly used in the rehabilitation process of ankle injuries; however, the exercise prescription guidelines for prescribing balance training are poorly understood. The aim of the present study was to determine if high or low volume balance training is more effective in improving postural sway after an 8 week balance training program utilising the same exercises. Seventeen subjects (14 male, 3 female) with a mean age of 24.06 &plusmn; 5.6 years were randomly allocated into a control group (CG), low volume training (LVT) or high volume training (HVT). All subjects had sustained at least two inversion ankle injuries within the last 18 months. Subjects completed 8 weeks of balance training of up to 30 mins duration, 3 times per week. LVT consisted of 40 repetitions for week 1, progressing to 90 repetitions by week 8. HVT consisted of 60 repetitions for week 1, progressing to 130 repetitions by week 8. The maximum centre of pressure (COP) excursion was obtained from the porce plate in the medial-lateral (ML) direction and subsequently used for pre-test and post-test analysis. After the 8 week training intervention, there was a significant (P&lt;0.001) difference in postural sway between pre and post testing for both the LVT (pre = 88.69mm &plusmn; 25.08mm, post = 72.17mm &plusmn; 27.53mm) and HVT (pre = 77.47mm &plusmn;10.57mm, post = 58.54mm &plusmn; 7.01mm) groups. There was no significant (P&gt;0.01) difference detected for improvements between the LVT and HVT, however reported effect sizes (ES) showed large effect size chances in the high volume training (ES = 1.7) whereas low volume training showed medium effect sizes changes (ES = 0.6). This preliminary study demonstrates the importance of training volume in the rehabilitation of ankle injuries, with the HVT being superior to LVT.<br /

King-Devick Performance Following Moderate and High Exercise Intensity Bouts.

International Journal of Exercise Science 10(4): 619-628, 2017. The King-Devick (K-D) test is a concise, noninvasive assessment of oculomotor and cognitive function that has been shown to detect sub-optimal brain performance following sports head trauma. Used in a number of sports as a sideline concussion assessment tool, the K-D test can be administered by non-medical personnel. However, the issue regarding the effect of exercise on K-D performance has not been fully explored. Using a randomized crossover design, this study aimed to compare the effect of two intensities of exercise on K-D performance. Twenty males (21.2 ± 1.9 years) completed the K-D test prior to and after 15 min of either moderate (65% of age-predicted maximal heart rate) and high intensity (80% of age-predicted maximal heart rate) exercise bouts, separated by one week. Significant differences were found in working heart rate and ratings of perceived exertion consistent with exercise intensities. K-D performance did not change after moderate exercise, however a significant improvement (5.4%) was observed after high intensity exercise. Based upon these findings, it appears that high intensity exercise can influence test performance and administrators of the test need to be aware of the arousal state a player is prior to K-D test administration to ensure objective measurement