Gender typing of sports: an investigation of Metheny's classification

The purpose of this study was to investigate if children perceived certain sports to be masculine, feminine, or neutral. Students attending a University Laboratory school (grades K-12) were asked to fill out a survey about sports during a class period, Children in grades K-6 were given a sport (such as baseball) and asked if a boy named David would play it, if a girl named Jane would play it, or if both David and Jane would play the sport. Students in grades 7-12 were asked to name their favorite athlete or team and sport and indicate what sports they felt was best for a girl and a boy. Then they were given a list of sports and asked to indicate, using a 5-point Likert-type scale, whether they believed the sport was masculine, neutral, or feminine. Results from loglinear analyses indicated that students sex-typed certain sports, such as aerobics and football. Additionally, although some responses from students in grades 7-12 indicated that individuals should be able to play any sport they wanted, there were many gendered rsponses in terms of what sport(s) girls and boys should participate in. The results are discussed with reference to Metheny's categories of permissible sports for girls and in the framework of the gender typing of sport.     

Detecting and correcting errors in rapid aiming movements: effects of movement time, distance, and velocity

According to closed-loop accounts of motor control, movement errors are detected by comparing sensory feedback to an acquired reference state. Differences between the reference state and the movement-produced feedback results in an error signal that serves as a basis for a correction. The main question addressed in the current study was how distance, movement time, and velocity influence both spatial or temporal error detection. Forty college-aged participants (30 women and 10 men) performed rapid aiming movements over 30 degrees or 50 degrees in either 210 ms or 350 ms without vision. The participants verbally estimated the distance moved and the movement time during acquisition before knowledge of results was given and during an immediate retention test without knowledge of results. Spatial and temporal objective-subjective correlations were greater in the 210-ms condition compared to the 350-ms condition, but were not related to movement velocity.     

Influence of perceived competence and causal dimension orientation on expectations, persistence, and performance during perceived failure

This investigation was conducted to compare the influence of high and low perceived competence (PC) and various causal dimension orientations on expectations, persistence, and performance while perceiving failure on a motor task. Based on a response to a PC scale, 84 junior high school students were selected to participate in this study. Separately, 42 low and 42 high PC subjects were oriented to perceive their performance on a stabilometer balancing task as due to: (a) internal, controllable, unstable factors (ICU); (b) internal, uncontrollable, stable factors (IUS); or (c) nothing in particular (NDO). Subjects then received fictitious negative feedback over 15 trials. Results revealed that persistence, expectations, and performance dependent measures were significant for PC and Causal Dimension groups. More specifically, the High PC group persisted longer, had higher expectations, and performed significantly better than the Low PC group. Furthermore, the subjects presented ICU orientations persisted for a longer amount of time, revealed higher expectations over trials, and performed significantly better over trials than the subjects in the IUS and NDO groups. These findings suggest that perceived competence and causal dimensional orientations influence children's expectations, persistence, and performance when perceiving failure on a motor task.     

The effect of pre-exercise carbohydrate feedings on the intensity that elicits maximal fat oxidation

The aim of the present study was to examine the effect of ingesting 75 g of glucose 45 min before the start of a graded exercise test to exhaustion on the determination of the intensity that elicits maximal fat oxidation (Fatmax). Eleven moderately trained individuals (VO2max: 58.9 +/- 1.0 ml x kg(-1) x min(-1); mean +/- sx), who had fasted overnight, performed two graded exercise tests to exhaustion, one 45 min after ingesting a placebo drink and one 45 min after ingesting 75 g of carbohydrate in the form of glucose. The tests started at 95 W and the workload was increased by 35 W every 3 min. Gas exchange measures and heart rate were recorded throughout exercise. Fat oxidation rates were calculated using stoichiometric equations. Blood samples were collected at rest and at the end of each stage of the test. Maximal fat oxidation rates decreased from 0.46 +/- 0.06 to 0.33 +/- 0.06 g min(-1) when carbohydrate was ingested before the start of exercise (P < 0.01). There was also a decrease in the intensity which elicited maximal fat oxidation (60.1 +/- 1.9% vs 52.0+3.4% VO2max) after carbohydrate ingestion (P < 0.05). Maximal power output was higher in the carbohydrate than in the placebo trial (346 +/- 12 vs 332 +/- 12 W) (P < 0.05). In conclusion, the ingestion of 75 g of carbohydrate 45 min before the onset of exercise decreased Fatmax by 14%, while the maximal rate of fat oxidation decreased by 28%.     

Validation of MET estimates and step measurement using the ActivPAL physical activity logger

The purpose of this study was to determine the validity of the metabolic equivalent (MET) equation and step rate function of the ActivPAL? physical activity logger in a group of females. Using a standard treadmill protocol, 62 females aged 15-25 years walked on a treadmill at speeds between 3.2 and 7.0 km · h(-1) while wearing an ActivPAL. Oxygen consumption was measured using expired gas analysis at each speed and METs for each speed were estimated based on each participant's own resting metabolic rate. A sub-set of 18 participants also wore an Actigraph. Results showed that the in-built equation in the ActivPAL significantly underestimated (P < 0.001) METs under treadmill conditions at higher intensities. The ActivPAL equation is based on step rate yet the relationship between counts and measured METs (r = 0.76; P < 0.001) is stronger than that between steps and measured METs (r = 0.59; P < 0.001). Both the ActivPAL and Actigraph step functions showed no significant difference (P > 0.05) to video recorded step rate except at the slowest walking speed where the Actigraph significantly underestimated steps (P < 0.05). The development of a new equation based on the counts-METs relationship that includes a variety of speeds and activities would be useful. The ActivPAL step function performs better than the Actigraph at the slowest walking speed under treadmill conditions.     

Trial-by-trial analysis or averaging: implications for electromyographic models of rapid limb control

The control of human limb movement has been the focus of research for more than a century. A major issue to emerge from this work is the manner in which the central nervous system regulates electromyographic (EMG) activity to produce movements that differ in distance, velocity, and movement time. However the different methods of analysis often used to analyze EMG data could result in different kinematic-EMG relationships. In this study, participants performed an elbow flexion task to one of five distance goals (between 5 degrees and 50 degrees) using three movement speeds. EMG data from the right elbow flexors were compared using a trial-by-trial analysis and one based on averaged data. Averaging across trials underestimated biceps EMG amplitude at all movement distances and speeds compared to a trial-by-trial analysis. Averaging overestimated EMG burst duration compared to the trial-by-trial analysis. Peak agonist EMG amplitude was positively related to distance and inversely related to movement time. Agonist EMG duration was constant for movement distances less than 30 degrees but increased in the 50 degrees condition. The results support the view that peak EMG amplitude and duration can be controlled independently, but EMG duration changes only for longer distance movements when additional force is required.     

The effect of acceleration signal processing for head impact numeric simulations

Brain injury research in sport employs a variety of physical models equipped with accelerometers. These acceleration signals are commonly processed using filters. The purpose of this research was to determine the effect of applying filters with different cutoff frequencies to the acceleration signals used as input for finite element modeling of the brain. Signals were generated from reconstructions of concussion events from American football and ice hockey in the laboratory using a Hybrid III headform. The resulting acceleration signals were used as input for the University College Dublin Brain Trauma Model after being processed with filters. The results indicated that using a filter with a cutoff of 300 Hz or higher had little effect on the resulting strain measures. In some cases there was some effect of the filters on the peak linear (8–30g) and rotational measures (1000–4000 rad/s²), but little effect on the finite element strain result (approximately 2–6 %). The short duration and high magnitude accelerations, such as the puck impact, were most affected by the cutoff frequency of different filters.     

Embedded programming and real-time signal processing of swimming strokes

The research outlined in this paper was conducted to allow real-time processing, transmission and presentation of data to swimming coaches and subsequently their swimmers in a training environment, focused on providing information relevant to strokes in free swimming. This was achieved using a wearable wireless sensor and embedded programming techniques, using accelerations involved in the swimming stroke to provide relevant features for coaches. Current methods used do not offer real-time response to coaches, which results in the lack of real-time feedback and significantly increased post-session analysis time. Filtering and signal processing algorithms are described here, which allow real-time data analysis to be embedded within a wireless sensor node. The system significantly reduces the time for processing acquired data and has delivered a novel monitoring device suitable for operation within the harsh environment of the pool.     

Glenohumeral joint rotation range of motion in competitive swimmers

Much research has examined shoulder range of motion adaptations in overhead-unilateral athletes. Based on the void examining overhead-bilateral athletes, especially competitive swimmers, we examined shoulder external rotation, isolated internal rotation, composite internal rotation, and total arc of motion range of motion of competitive swimmers. The range of motion of registered competitive swimmers (n = 144, age = 12-61 years) was compared by limb (dominant, non-dominant), sex, and age group (youth, high school, college, masters). Significantly (P < 0.05) greater dominant external rotation was observed for both men and women high school and college swimmers, youth women swimmers, and men masters swimmers compared with the non-dominant limb. The isolated internal rotation (glenohumeral rotation), composite internal rotation (glenohumeral rotation plus scapulothoracic protraction), and total arc of motion (external rotation plus composite internal rotation) of the non-dominant limb was significantly greater than that of the dominant limb by sex and age group. Youth and high school swimmers demonstrated significantly greater composite internal rotation than college and masters swimmers. Youth swimmers displayed significantly greater total arc of motion than all other age groups. These data will aid in the interpretation of shoulder range of motion values in competitive swimmers during preseason screenings, injury evaluations and post-rehabilitation programmes, with the results suggesting that differences exist in bilateral external rotation, isolated internal rotation, composite internal rotation, and total arc of motion range of motion.