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

Fisheries-dependent indicators of climate change in Western Australia WAMSI:Sub-project 4.2.3

The use of fishery-dependent data may be a cost-effective way of assessing whether there have been any changes in the distribution and relative abundance of species. Such indicators are part of an ongoing data gathering system and the costs are relatively low compared to those of a fishery-independent field program. Fishery-dependent data may therefore be obtained at a higher frequency and allow detection of changes faster than would be possible from the results from the direct sampling of specific sites within entire ecosystems

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