The mediating role of intention and stages of change in physical activity among adults with physical disabilities: an integrative framework

The study's purpose was to identify the mediating role of intention and the stages of change (SOC) in physical activity (PA) over a 6-month period using two models (theory of planned behavior [TPB] and TPB/SOC). Participants were 143 adults with physical disabilities (70.68% response rate; M age = 46.03). The TPB constructs, SOC (time 1), and PA (time 2) were assessed using standardized self-report questionnaires. Based on path analyses, attitude had the highest effect on intention and SOC followed by perceived behavioral control within both well-fit models. The variance in PA explained by the first (TPB) and second (TPB/SOC) models was 16% and 28% respectively. In the just identified model of TPB/SOC, the direct effect of SOC on physical activity remained strong (gamma(soc.pa) = .45) and SOC approached full mediation through attitude. Health promotion interventions need to include both intention and behavior elements (SOC) reinforcing increased PA value and barrier elimination.     

Optimized versus corrected peak power during friction-braked cycle ergometry in males and females

The aim of this study was to compare optimization and correction procedures for the determination of peak power output during friction-loaded cycle ergometry. Ten male and 10 female sports students each performed five 10-s sprints from a stationary start on a Monark 864 basket-loaded ergometer. Resistive loads of 5.0, 6.5, 8.0, 9.5, and 11.0% body weight were administered in a counterbalanced order, with a recovery period of 10 min between sprints. Peak power was greater and occurred earlier, with less work having been done before the attainment of peak power, when the data were corrected to account for the inertial and frictional characteristics of the ergometer. Corrected peak power was independent of resistive load (P > 0.05), whereas uncorrected peak power varied as a quadratic function of load (P < 0.001). For males and females, optimized peak power (971 +/- 122 and 668 +/- 37 W) was lower (P < 0.01) than either the highest (1074 +/- 111 and 754 +/- 56 W respectively) or the mean (1007 +/- 125 and 701 +/- 45 W respectively) of the five values for corrected peak power. Optimized and mean corrected peak power were highly correlated both in males (r = 0.97, P < 0.001) and females (r = 0.96, P < 0.001). The difference between optimized and mean corrected peak power was 37 +/- 30 W in males and 33 +/- 14 W in females, of which approximately 15 W was due to the correction for frictional losses. We conclude that corrected peak power is independent of resistive load in males and females.     

The relationship between shoulder alignment and elbow joint angle in cricket fast-medium bowlers

The aim of this study was to examine the relationship between shoulder alignment and elbow angle during the delivery action of fast-medium bowlers. The elbow and upper trunk alignment were recorded for 13 high-performance bowlers (mean age 20 years) using a 12-camera Vicon motion analysis system operating at 250 Hz. The three highest velocity trials for "good" and "short" length deliveries were analysed. Results showed that bowlers with a more front-on shoulder alignment at back-foot impact and when the upper arm was horizontal to the ground experienced a significantly greater elbow flexion--extension range when compared with those who had a more side-on orientation at the same point in the delivery action. Bowlers with greater shoulder counter-rotation also recorded higher elbow flexion and subsequently extension during the period from upper arm horizontal to ball release. Shoulder alignment and elbow angles were similar for "short" and "good" length deliveries. It was concluded that bowlers with a more front-on shoulder orientation at back-foot impact demonstrated a higher elbow extension from upper arm horizontal to ball release and are therefore more likely to infringe International Cricket Council elbow tolerance levels, compared with those who adopt a more side-on shoulder orientation at back-foot impact.     

The effect of submaximal exercise on recovery hemodynamics and thermoregulation in men and women

Five women and 5 men were studied to examine the effects of submaximal exercise on thermoregulatory and hemodynamic variables during recovery in two environments: (a) control (C), 22 degrees C, 33% rh; and (b) hot humid (H), 32 degrees C. The participants exercised on a cycle ergometer at 60% of peak oxygen consumption for 35 min prior to 90 min of seated recovery. Sessions were identical, except for environment. Variables evaluated (p < .05) were: core temperature (TR), mean skin temperature (Ts), sweat rate (SR), heart rate (HR), stroke index (SI), cardiac index (CI), forearm blood flow (FBF), systolic blood pressure (SBP), and diastolic blood pressure (DBP). Men and women exhibited similar patterns of TR, Ts, and SR in both environments. Ts and SR (collapsed means for gender) were higher in the H than in the C. DBP was higher in men than in women throughout recovery in both environments. With combined means for gender, HR was higher in the H than in the C. CI, SI, FBF, and SBP were similar in both environments and returned to baseline within 15 min into recovery. These data suggest that heat dissipation during extended recovery was accomplished with similar contributions of cutaneous vasodilation and sweating in M and F. Furthermore, the moderate exercise level did not influence hemodynamics beyond 15 min of recovery in either environment.     

Decreasing the proportion of self-control trials during the acquisition period does not compromise the learning advantages in a self-controlled context

The present experiment examined the learning effects of participants self-controlling their receipt of knowledge of results (KR) on all or half of their acquisition trials (50%). For participants who were provided 50% self-control, the first half of their acquisition period consisted of receiving KR on all trials, or according to a faded-KR schedule. Participants practiced a sequential timing task. The results showed that independent of practice condition, participants who self-controlled their KR during the acquisition period demonstrated superior performance compared to the respective yoked conditions in the retention and transfer portion of the experiment. These results extend previous research by suggesting that decreasing the proportion of self-control trials does not compromise learning in a self-controlled context.     

Use of dual-task methodology for skill assessment and development: examples from rugby league

We assessed the attentional demands of drawing and passing in rugby league players and investigated the effects of single-task and dual-task training on the acquisition, retention, and transfer of skill in these athletes. In Study 1, high-skilled and lesser-skilled rugby league players performed a standardized 2-on-1 drill under single-task (primary skill in isolation) and dual-task (primary skill while performing a secondary verbal tone recognition task) conditions. No differences were detected in primary task performance between groups, although the performance of the high-skilled players was more resistant to skill decrement under dual-task conditions. In Study 2, high-performance rugby league players were randomly allocated to either a single-task or dual-task training group. Each group underwent 8 weeks of training between the pre- and post-test sessions. While the mean improvement for draw and pass proficiency under dual-task conditions in the dual-task training group was greater than in the single-task training group (10.0% vs. 2.3%), the differences, while providing a moderate effect size (d = 0.57), were not statistically significant. These results suggest that the attentional demands of drawing and passing are reduced in high-skilled rugby league players compared with their lesser-skilled counterparts. In addition, compared with single-task training, dual-task training appears to improve the ability to perform dual-task draw and pass tasks (possibly through an improvement in time-sharing skills). Further studies are required to verify the efficacy of dual-task training as a training stimulus.     

The value of a non-sport-specific motor test battery in predicting performance in young female gymnasts

Gymnastics talent identification focuses on the identification of young gymnasts who display characteristics for potential success in the future. The aim of this study was to identify which current performance characteristics are related to performance in competition 2 years later. Twenty-three female gymnasts aged 7-8 years completed a multidimensional test battery measuring anthropometric, physical, and coordinative characteristics and were technically evaluated by expert coaches. Two years later, the all-around competition results of those gymnasts now participating in elite (n = 12) and sub-elite (n = 11) competition were obtained. None of the initial measurements significantly correlated with the results of the sub-elite gymnasts 2 years later. For the elite gymnasts, a non-sport-specific motor test battery correlated strongly with the competition result, with more than 40% of the variation in competition performance being explained by the result on that test 2 years earlier. Neither the coaches' judgement nor the anthropometric and physical characteristics were sensitive enough to predict performance. A motor coordination test might be valuable in the early identification of gymnasts, as its discriminative and predictive qualities might be sufficiently powerful for selection within a relatively homogeneous population of gymnasts exhibiting similar anthropometric and physical profiles.     

Plasticity of human handedness: decreased one-hand bias and inter-manual performance asymmetry in expert basketball players

Athletes frequently have to adapt their skills to fast changes of play, often requiring the flexible execution of a particular movement skill with either hand. To assess the influence of sport-specific expertise and extensive sport training on human laterality, a video analysis of regular basketball games was performed for professional, semi-professional, and amateur players to investigate how non-dominant hand use and proficiency change with increasing expertise. Our results showed that the right-hand (i.e. dominant hand) bias in basketball players is reduced with increasing expertise (i.e., competitive level). Accordingly, we found that professional players use their non-dominant hand more often and with greater success than semi-professional and amateur players. This was true for most of the basketball-specific skills. Based on these results, we assume that increasing amounts of bilateral practice can lead to a shift in task-specific manual preference towards a higher use of both hands in competition, as well as to a higher proficiency for non-dominant hand actions in particular. From an applied perspective, the more frequent use and higher proficiency of the non-dominant hand in professional basketball players, compared with amateurs, suggests that the context-specific and skilled use of the non-dominant hand is crucial for successful play at higher competitive levels in the sport of basketball.     

Effects of cold water immersion on the recovery of physical performance and muscle damage following a one-off soccer match

The aim of this study was to assess the effects of a single session of cold or thermoneutral water immersion after a one-off match on muscular dysfunction and damage in soccer players. Twenty-male soccer players completed one match and were randomly divided into cryotherapy (10 min cold water immersion, 10°C, n = 10) and thermoneutral (10 min thermoneutral water immersion, 35°C, n = 10) groups. Muscle damage (creatine kinase, myoglobin), inflammation (C-reactive protein), neuromuscular function (jump and sprint abilities and maximal isometric quadriceps strength), and delayed-onset muscle soreness were evaluated before, within 30 min of the end, and 24 and 48 h after the match. After the match, the players in both groups showed increased plasma creatine kinase activity (30 min, 24 h, 48 h), myoglobin (30 min) and C-reactive protein (30 min, 24 h) concentrations. Peak jump ability and maximal strength were decreased and delayed-onset muscle soreness increased in both groups. However, differential alterations were observed between thermoneutral water and cold water immersion groups in creatine kinase (30 min, 24 h, 48 h), myoglobin (30 min), C-reactive protein (30 min, 24 h, 48 h), quadriceps strength (24 h), and quadriceps (24 h), calf (24 h) and adductor (30 min) delayed-onset muscle soreness. The results suggest that cold water immersion immediately after a one-off soccer match reduces muscle damage and discomfort, possibly contributing to a faster recovery of neuromuscular function.     

Impaired motor control after sport-related concussion could increase risk for musculoskeletal injury: Implications for clinical management and rehabilitation

This review presents a conceptual framework and supporting evidence that links impaired motor control after sport-related concussion(SRC)to increased risk for musculoskeletal injury.Multiple studies have found that athletes who are post-SRC have higher risk for musculoskeletal injury compared to their counterparts.A small body of research suggests that impairments in motor control are associated with musculoskeletal injury risk.Motor control involves the perception and processing of sensory information and subsequent coordination of motor output within the central nervous system to perform a motor task.Motor control is inclusive of motor planning and motor learning.If sensory information is not accurately perceived or there is interference with sensory information processing and cognition,motor function will be altered,and an athlete may become vulnerable to injury during sport participation.Athletes with SRC show neuroanatomic and neurophysiological changes relevant to motor control even after meeting return to sport criteria,including a normal neurological examination,resolution of symptoms,and return to baseline function on traditional concussion testing.In conjunction,altered motor function is demonstrated after SRC in muscle activation and force production,movement patterns,balance/postural stability,and motor task performance,especially performance of a motor task paired with a cognitive task(i.e.,dual-task condition).The clinical implications of this conceptual framework include a need to intentionally address motor control impairments after SRC to mitigate musculoskeletal injury risk and to monitor motor control as the athlete progresses through the return to sport continuum.