Mechanisms of anterior cruciate ligament injury in basketball: video analysis of 39 cases

BACKGROUND

The mechanisms of anterior cruciate ligament injury in basketball are not well defined.

PURPOSE

To describe the mechanisms of anterior cruciate ligament injury in basketball based on videos of injury situations.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Six international experts performed visual inspection analyses of 39 videos (17 male and 22 female players) of anterior cruciate ligament injury situations from high school, college, and professional basketball games. Two predefined time points were analyzed: initial ground contact and 50 milliseconds later. The analysts were asked to assess the playing situation, player behavior, and joint kinematics.

RESULTS

There was contact at the assumed time of injury in 11 of the 39 cases (5 male and 6 female players). Four of these cases were direct blows to the knee, all in men. Eleven of the 22 female cases were collisions, or the player was pushed by an opponent before the time of injury. The estimated time of injury, based on the group median, ranged from 17 to 50 milliseconds after initial ground contact. The mean knee flexion angle was higher in female than in male players, both at initial contact (15 degrees vs 9 degrees , P = .034) and at 50 milliseconds later (27 degrees vs 19 degrees , P = .042). Valgus knee collapse occurred more frequently in female players than in male players (relative risk, 5.3; P = .002).

CONCLUSION

Female players landed with significantly more knee and hip flexion and had a 5.3 times higher relative risk of sustaining a valgus collapse than did male players. Movement patterns were frequently perturbed by opponents.

CLINICAL RELEVANCE

Preventive programs to enhance knee control should focus on avoiding valgus motion and include distractions resembling those seen in match situations.

Valgus Knee Motion during Landing in High School Female and Male Basketball Players

PURPOSE

The purpose of this study was to utilize three-dimensional kinematic (motion) analysis to determine whether gender differences existed in knee valgus kinematics in high school basketball athletes when performing a landing maneuver. The hypothesis of this study was that female athletes would demonstrate greater valgus knee motion (ligament dominance) and greater side-to-side (leg dominance) differences in valgus knee angle at landing. These differences in valgus knee motion may be indicative of decreased dynamic knee joint control in female athletes.

METHODS

Eighty-one high school basketball players, 47 female and 34 male, volunteered to participate in this study. Valgus knee motion and varus-valgus angles during a drop vertical jump (DVJ) were calculated for each subject. The DVJ maneuver consisted of dropping off of a box, landing and immediately performing a maximum vertical jump. The first landing phase was used for the analysis.

RESULTS

Female athletes landed with greater total valgus knee motion and a greater maximum valgus knee angle than male athletes. Female athletes had significant differences between their dominant and nondominant side in maximum valgus knee angle.

CONCLUSION

The absence of dynamic knee joint stability may be responsible for increased rates of knee injury in females but is not normally measured in athletes before participation. No method for accurate and practical screening and identification of athletes at increased risk of ACL injury is currently available to target those individuals that would benefit from neuromuscular training before sports participation. Prevention of female ACL injury from five times to equal the rate of males would allow tens of thousands of young females to avoid the potentially devastating effects of ACL injury on their athletic careers.

Increased movement accuracy and reduced EMG activity as the result of adopting an external focus of attention

The performance and learning of motor skills has been shown to be enhanced if the performer adopts an external focus of attention (focus on the movement effect) compared to an internal focus (focus on the movements themselves) [G. Wulf, W. Prinz, Directing attention to movement effects enhances learning: a review, Psychon. Bull. Rev. 8 (2001) 648-660]. While most previous studies examining attentional focus effects have exclusively used performance outcome (e.g., accuracy) measures, in the present study electromyography (EMG) was used to determine neuromuscular correlates of external versus internal focus differences in movement outcome. Participants performed basketball free throws under both internal focus (wrist motion) and external focus (basket) conditions. EMG activity was recorded for m. flexor carpi radialis, m. biceps brachii, m. triceps triceps brachii, and m. deltoid of each participant's shooting arm. The results showed that free throw accuracy was greater when participants adopted an external compared to an internal focus. In addition, EMG activity of the biceps and triceps muscles was lower with an external relative to an internal focus. This suggests that an external focus of attention enhances movement economy, and presumably reduces "noise" in the motor system that hampers fine movement control and makes the outcome of the movement less reliable.

Leisure-time physical activity in school environments: an observational study using SOPLAY

BACKGROUND

Schools provide settings for physical activity (PA), but objective tools for measuring PA are lacking. We assessed an instrument to directly observe group PA and measured the leisure-time PA of adolescents throughout the school day.

METHODS

Leisure-time PA was studied by direct observation in 24 middle schools in Southern California using SOPLAY (System for Observing Play and Leisure Activity in Youth). SOPLAY uses momentary time sampling to record the activity of each individual as sedentary, walking, or very active.

RESULTS

The largest proportion of students visited activity areas at lunch time (19.5%), followed by before (4. 1%) and after school (2.1%). More boys than girls visited activity areas before school (33.4 vs 7.7) and at lunch time (148.8 vs 36.7). Boys in areas engaged in more moderate to vigorous PA than girls before school (59.6 vs 40%) and at lunch time (67.7 vs 51.7%).

CONCLUSIONS

Few students use opportunities to be physically active during lesiure time at school. Policies and environmental manipulations (e.g., supervision, equipment, structured programs) are needed to attract more adolescents, especially girls, to existing activity areas. The feasibility of SOPLAY for measuring group PA was established.

A prevention strategy to reduce the incidence of injury in high school basketball: a cluster randomized controlled trial

OBJECTIVE

To examine the effectiveness of a sport-specific balance training program in reducing injury in adolescent basketball.

DESIGN

Cluster randomized controlled trial.

SETTING

Twenty-five high schools in Calgary and surrounding area.

SUBJECTS

Nine hundred and twenty high school basketball players (ages 12-18).

INTERVENTION

Subjects were randomly allocated by school to the control (n = 426) and training group (n = 494). Both groups were taught a standardized warm-up program. The training group was also taught an additional warm-up component and a home-based balance training program using a wobble board.

MAIN OUTCOME MEASURES

All injuries occurring during basketball that required medical attention and/or caused a player to be removed from that current session and/or miss a subsequent session were then recorded and assessed by a team therapist who was blinded to training group allocation.

RESULTS

A basketball-specific balance training program was protective of acute-onset injuries in high school basketball [RR = 0.71 (95% CI; 0.5-0.99)]. The protective effect found with respect to all injury [RR = 0.8 (95% CI; 0.57-1.11)], lower-extremity injury [RR = 0.83 (95% CI; 0.57-1.19)], and ankle sprain injury [RR = 0.71 (95% CI; 0.45-1.13)] were not statistically significant. Self-reported compliance to the intended home-based training program was poor (298/494 or 60.3%).

CONCLUSIONS

A basketball-specific balance training program was effective in reducing acute-onset injuries in high school basketball. There was also a clinically relevant trend found with respect to the reduction of all, lower-extremity, and ankle sprain injury. Future research should include further development of neuromuscular prevention strategies in addition to further evaluation of methods to increase compliance to an injury-prevention training program in adolescents.

Treatment of ankle sprains in young athletes

To study the incidence of fibulocollateral ligament ankle sprains in the young male athlete, a survey of 84 varsity basketball players was done. Seventy percent of the players had a history of an ankle sprain. Eighty percent of those with a positive history had multiple sprains. Most of the injuries were mild, but in 32% of the injuries, the athlete missed more than 2 weeks of play. No medical attention was sought in 55% of the cases. About 50% of the athletes with a sprain had residual symptoms from their injuries; 15% of the injured athletes felt that their residual symptoms compromised their playing performance. This article emphasizes the potential seriousness of the ankle sprain in the young athlete and presents a recommended method of management, including assessment of severity, treatment, and rehabilitation.

Trust in leadership and team performance: evidence from NCAA basketball

This study empirically examined the relationship between trust, leadership, and team performance with 2 objectives. The 1st objective was to empirically examine an assumption found in several literatures--that a team's trust in its leader has a significant effect on the team's performance. The 2nd objective was to explore a more complex and dynamic relationship between trust and team performance whereby trust in leadership mediates the relationship between past team performance and future team performance. This relationship is derived by combining theories of trust with an attributional theory of leadership. Survey and archival data from a sample of men's college basketball teams provides support for both hypotheses, indicating that trust in leadership is both a product and a determinant of team performance.

Testosterone changes during vicarious experiences of winning and losing among fans at sporting events

Basking in reflected glory, in which individuals increase their self-esteem by identifying with successful others, is usually regarded as a cognitive process that can affect behavior. It may also involve physiological processes, including changes in the production of endocrine hormones. The present research involved two studies of changes in testosterone levels among fans watching their favorite sports teams win or lose. In the first study, participants were eight male fans attending a basketball game between traditional college rivals. In the second study, participants were 21 male fans watching a televised World Cup soccer match between traditional international rivals. Participants provided saliva samples for testosterone assay before and after the contest. In both studies, mean testosterone level increased in the fans of winning teams and decreased in the fans of losing teams. These findings suggest that watching one's heroes win or lose has physiological consequences that extend beyond changes in mood and self-esteem.

Partial tears of the anterior cruciate ligament. Progression to complete ligament deficiency

In a prospective seven-year study, we treated 32 patients with partial ruptures of the anterior cruciate ligament (ACL) verified by arthroscopy. Twelve knees (38%) progressed to complete ACL deficiency with positive pivot shift tests and increased anteroposterior translation on tests with the KT-1000 arthrometer. Patients with partial ACL tears frequently had limitation for strenuous sports, while those developing ACL deficiency had additional functional limitations involving recreational activities. Three factors were statistically significant in predicting which partial tears would develop complete ACL deficiency: the amount of ligament tearing--one-fourth tears infrequently progressed, one-half tears progressed in 50% and three-fourth tears in 86%; a subtle increase in initial anterior translation; and the occurrence of a subsequent re-injury with giving-way.

Testosterone, cortisol, and mood in a sports team competition

In humans, hormonal responses to winning/losing and their relationships to mood and status change have mostly been examined in individual athletic competitions. In this study, the salivary testosterone (T) and cortisol (C) and mood responses to a real match between two professional basketball teams were investigated. Data about individuals' contributions to outcome, performance appraisal, and attribution of outcome to internal/external factors were also collected. Results did not show statistically significant different T and C responses depending on the outcome. Negative mood was significantly enhanced, especially in the losers, while winners showed a better appraisal of team performance and a more internal attribution. T response did not show a significant relationship with mood changes, but it correlated positively with the "score/time playing" ratio, an indicator of individual participation in the outcome. Furthermore, T response correlated negatively with external attribution in winners and positively in losers. These results indicate that in a real, highly competitive situation, T changes are not directly a response to the outcome, but rather to the contribution the individual makes to it and to the causes he attributes.

Patellar tendinopathy in junior basketball players: a controlled clinical and ultrasonographic study of 268 patellar tendons in players aged 14-18 years

Anterior knee pain is a common presenting complaint amongst adolescent athletes. We hypothesised that patellar tendinopathy may occur at a younger age than is generally recognised. Thus, we studied the patellar tendons in 134 elite 14- to 18-year-old female (n=64) and male (n=70) basketball players and 29 control swimmers (17 female, 12 male) clinically and with ultrasonography. We found that of 268 tendons, 19 (7%) had current patellar tendinopathy on clinical grounds (11% in males, 2% in females). Twenty-six percent of the basketball players' patellar tendons contained an ultrasonographic hypoechoic region. Ultrasonographic abnormality was more prevalent in the oldest tertile of players (17-18 years) than the youngest tertile (14-15.9 years). Of tendons categorised clinically as 'Never patellar tendinopathy', 22% had an ultrasonographic hypoechoic region nevertheless. This study indicates that patellar tendinopathy can occur in 14- to 18-year-old basketball players. Ultrasonographic tendon abnormality is 3 times as common as clinical symptoms.

The natural history and treatment of delayed union stress fractures of the anterior cortex of the tibia

This study presents eight patients with stress fracture of the anterolateral cortex of the midshaft of the tibia. All of the patients, ranging in age from 14 to 23 years, were competitive basketball players who experienced pain while running or jumping for an average of 4.4 months before the diagnosis was made. Eight patients were treated with rest and/or pulsing electromagnetic field therapy. Although one of the patients required bone grafting procedure, all eight of these patients showed complete healing and were able to return to full activity after an average of 8.7 months of treatment. They have remained asymptomatic for an average of 14.7 months. The overall time from initial symptoms to return to competition averaged 12.5 months in this group of athletes. The results presented in this paper suggest that rest and pulsing electromagnetic field therapy may result in healing in some patients with delayed union stress fractures of the anterolateral cortex of the midshaft of the tibia. Although this injury is associated with a prolonged healing period, seven of eight patients with adequate followup in our study were able to return to competition without complications following treatment. One patient was asymptomatic for 33 months before experiencing a reinjury. In conclusion, we feel that diagnosis of stress fracture should be primary consideration in basketball players presenting with a prolonged history of pain on the anterolateral aspect of the midthird of the tibia. Once the diagnosis is made we recommend initial treatment consist of rest and external electrical stimulation for a minimum time of 3 to 6 months prior to considering surgical intervention.

Viral dynamics of acute SARS-CoV-2 infection and applications to diagnostic and public health strategies

SARS-CoV-2 infections are characterized by viral proliferation and clearance phases and can be followed by low-level persistent viral RNA shedding. The dynamics of viral RNA concentration, particularly in the early stages of infection, can inform clinical measures and interventions such as test-based screening. We used prospective longitudinal quantitative reverse transcription PCR testing to measure the viral RNA trajectories for 68 individuals during the resumption of the 2019-2020 National Basketball Association season. For 46 individuals with acute infections, we inferred the peak viral concentration and the duration of the viral proliferation and clearance phases. According to our mathematical model, we found that viral RNA concentrations peaked an average of 3.3 days (95% credible interval [CI] 2.5, 4.2) after first possible detectability at a cycle threshold value of 22.3 (95% CI 20.5, 23.9). The viral clearance phase lasted longer for symptomatic individuals (10.9 days [95% CI 7.9, 14.4]) than for asymptomatic individuals (7.8 days [95% CI 6.1, 9.7]). A second test within 2 days after an initial positive PCR test substantially improves certainty about a patient's infection stage. The effective sensitivity of a test intended to identify infectious individuals declines substantially with test turnaround time. These findings indicate that SARS-CoV-2 viral concentrations peak rapidly regardless of symptoms. Sequential tests can help reveal a patient's progress through infection stages. Frequent, rapid-turnaround testing is needed to effectively screen individuals before they become infectious.

The effects of cooperation and competition on intrinsic motivation and performance

The authors examined the effects of competition and cooperation on intrinsic motivation and performance in 4 studies. Across 3 behavioral studies that involved shooting a basketball, no differences were observed between competition and cooperation on task enjoyment or performance. However, the combination of competition and cooperation (intergroup competition) consistently led to higher levels of intrinsic motivation, and in 2 of the 3 studies, performance. In a questionnaire study, the authors replicated the positive effects of intergroup competition on enjoyment and examined process measures that might account for these effects. These findings suggest that competition and cooperation both have positive aspects and that structuring recreational activities to include both can facilitate high levels of both intrinsic motivation and performance.

A catastrophe model of anxiety and performance

An experiment is reported which tests Fazey & Hardy's (1988) catastrophe model of anxiety and performance. Eight experienced basketball players were required to perform a set shooting task, under conditions of high and low cognitive anxiety. On each of these occasions, physiological arousal was manipulated by means of physical work in such a way that subjects were tested with physiological arousal increasing and decreasing. Curve-fitting procedures followed by non-parametric tests of significance confirmed (p less than .002) Fazey & Hardy's hysteresis hypothesis: namely, that the polynomial curves for the increasing vs. decreasing arousal conditions would be horizontally displaced relative to each other in the high cognitive anxiety condition, but superimposed on top of one another in the low cognitive anxiety condition. Other non-parametric procedures showed that subjects' maximum performances were higher, their minimum performances lower, and their critical decrements in performance greater in the high cognitive anxiety condition than in the low cognitive anxiety condition. These results were taken as strong support for Fazey & Hardy's catastrophe model of anxiety and performance. The implications of the model for current theorizing on the anxiety-performance relationship are also discussed.

Progressive dehydration causes a progressive decline in basketball skill performance

PURPOSE

To determine the effect of 1, 2, 3, and 4% dehydration (DEH) versus euhydration (EUH) on basketball performance in adult male players.

METHODS

Seventeen 17- to 28-yr-old male basketball players completed 3 h of interval treadmill walking (40 degrees C and 20% relative humidity) with or without fluid replacement. Subjects completed six trials in random order: 1) EUH with a carbohydrate-electrolyte solution (CES), 2) EUH control (flavored water with 0% carbohydrate and 18 mM sodium), 3) 1% DEH, 4) 2% DEH, 5) 3% DEH, and 6) 4% DEH. After a 70-min recovery period, subjects performed a sequence of continuous basketball drills designed to simulate a fast-paced game. Measures of overall skill performance during the 80-min game included 1) total time to complete basketball-specific movement drills (sprinting, defensive slides, sprinting-defensive slides combination, and repetitive jumping drills) and 2) total number of shots (foul-line and baseline jump shots, layups, three-point, 15-ft, free throws) made per game.

RESULTS

Performance during all timed and shooting drills declined progressively as % DEH increased. Total time to complete basketball-specific movement drills was slower (1%: + 7 +/- 6; 2%: + 20 +/- 5 (P < 0.05); 3%: + 26 +/- 7 (P < 0.005); 4%: + 57 +/- 9 (P < 0.0001) s), and fewer shots were made during DEH versus EUH control (1%: -5 +/- 1; 2%: -6 +/- 2 (P < 0.05); 3%: -8 +/- 2 (P < 0.005); 4%: -10 +/- 1 (P < 0.0001) shots made). There were no significant differences in performance between CES and EUH control.

CONCLUSION

Basketball players experienced a progressive deterioration in performance as DEH progressed from 1 to 4%. The threshold, or % DEH at which the performance decrement reached statistical significance, was 2% for combined timed and shooting drills.

Body weight changes and voluntary fluid intakes during training and competition sessions in team sports

Fluid losses (measured by body weight changes) and voluntary fluid intakes were measured in elite basketball, netball, and soccer teams during typical summer and winter exercise sessions to determine fluid requirements and the degree of fluid replacement. Each subject was weighed in minimal clothing before and immediately after training, weights, and competition sessions; fluid intake, duration of exercise, temperature and humidity, and opportunity to drink were recorded. Sweat rates were greatest during competition sessions and significantly lower during weights sessions for all sports. Seasonal variation in dehydration (%DH) was not as great as may have been expected, particularly in sports played indoors. Factors influencing fluid replacement during exercise included provision of an individual water bottle, proximity to water bottles during sessions, encouragement to drink, rules of the game, duration and number of breaks or substitutions, and awareness of personal sweat rates. Guidelines for optimizing fluid intakes in these three sports are provided.

Bone density in eumenorrheic female college athletes

Information is limited on the effect of exercise on bone density in young eumenorrheic athletes. We studied 12 Caucasian intercollegiate volleyball players (V), nine basketball players (B), ten swimmers (S), and 13 non-athletes (N) with bone density measurements by photon absorptiometry of their calcaneus and lumbar spine (L2-L4). The effect of athletic status on bone density was analyzed by multivariate analysis of covariance, with height and weight as covariates. The bone densities reported below are mean +/- SE, adjusted for the covariates; units = g.cm-2, P less than 0.005. The swimmers had a significantly lower mean density in the lumbar spine than all other groups; the non-athletes' mean density was also lower than that of volleyball players (V = 1.31 +/- 0.03, B = 1.26 +/- 0.04, N = 1.18 +/- 0.03, S = 1.05 +/- 0.03). The volleyball and basketball players' mean calcaneal densities were greater than those of the swimmers and non-athletes (V = 0.530 +/- 0.017, B = 0.564 +/- 0.023, N = 0.438 +/- 0.018, S = 0.375 +/- 0.019). The higher bone densities for athletes in vertical weight-bearing activities are consistent with some but not all published data. The swimmers' low bone density in the lumbar spine, less than published values for amenorrheic runners, was unexpected.

Effects of physical exercise on quality of life, exercise capacity and pulmonary function in children with asthma

OBJECTIVE

To investigate the effects of regular submaximal exercise on quality of life, exercise capacity and pulmonary function in asthmatic children.

PATIENTS AND METHODS

Sixty-two children with mild-moderate asthma (mean age 10.4 (SD 2.1) years) were randomly allocated into exercise and control groups. The exercise group underwent a moderately intensive basketball training program for 8 weeks. A home respiratory exercise program was advised to both groups. Pediatric Asthma Quality of Life Questionnaire (PAQLQ) was used for the evaluation of activity limitation, symptoms and emotional functions. Exercise capacity was evaluated through the physical work capacity (PWC 170 test) on a cycle ergometer and 6-minute walk test. Spirometric tests were also performed and medication and symptom scores were recorded.

RESULTS

Although PAQLQ scores improved in both groups, the improvement in the exercise group was significantly higher. The exercise group performed better in the PWC 170 and 6-minute walk tests, whereas no improvement was detected in the control group at the end of the trial. Medication scores improved in both groups, but symptom scores improved only in the exercise group. No significant changes were detected in pulmonary function in either group, except for peak expiratory flow values in the exercise group.

CONCLUSION

Eight weeks of regular submaximal exercise has beneficial effects on quality of life and exercise capacity in children with asthma. Submaximal basketball training is an effective alternative exercise program for asthmatic children.

Stress fractures of the medial malleolus

Six athletes, all engaged in running activities at the time of injury, presented with tenderness over the medial malleolus and ankle effusion. Three patients had a fracture line which could be seen on radiographs. These patients were treated by open reduction and internal fixation using two 4.0 cancellous screws. The other three patients had normal radiographs but bone scans showed increased uptake over the medial malleolus. These patients were treated with cast and immobilization. We believe that each of these patients suffered a stress fracture of the medial malleolus. We suggest that the possibility of a stress fracture be considered in the differential diagnosis of patients who present with 1) chronic or subacute pain over the medial malleolus and ankle effusion, and 2) a history of running activity at the time of injury or running activities aggravating the pain. Bone scans appear to be more sensitive than radiographs in detecting a stress fracture of the medial malleolus. We propose that athletes with radiographic signs of a medial malleolar fracture who desire early return to full participation should be treated by open reduction and internal fixation. For these patients, early motion can be initiated. Other athletes whose fracture cannot be detected on radiographs but whose malleolus shows increased uptake in the area on bone scans can be treated nonsurgically with immobilization and then progressive increase in activity. All of our patients returned to full activity between 6 and 8 weeks after treatment was initiated.

Cutaneous Community-acquired Methicillin-resistant Staphylococcus aureus Infection in Participants of Athletic Activities

OBJECTIVES

Cutaneous community-acquired methicillin-resistant Staphylococcus aureus (CAMRSA) has been identified in otherwise healthy individuals either with or without methicillin-resistant S. aureus (MRSA)-associated risk factors who participate in athletic activities. The purpose of this study was to describe the clinical features of CAMRSA skin infection that occurred in university student athletes, evaluate the potential mechanisms for the transmission of MRSA infection of the skin in participants of athletic activities, and review the measures for preventing the spread of cutaneous CAMRSA infection in athletes.

METHODS

A retrospective chart review of the student athletes from the University of Houston whose skin lesions were evaluated at the Health Center and grew MRSA was performed. The clinical characteristics and the postulated mechanisms of cutaneous MRSA infection in the athletes were compared with those previously published in reports of CAMRSA skin infection outbreaks in other sports participants.

RESULTS

Cutaneous CAMRSA infection occurred in seven student athletes (four women and three men) who were either weight lifters (three students) or members of a varsity sports team: volleyball (two women), basketball (one woman), and football (one man). The MRSA skin infection presented as solitary or multiple, tender, erythematous, fluctuant abscesses with surrounding cellulitis. The lesions were most frequently located in the axillary region (three weight lifters), on the buttocks (two women), or on the thighs (two women). The drainage from all of the skin lesions grew MRSA, which was susceptible to clindamycin, gentamicin, rifampin, trimethoprim/sulfamethoxazole, and vancomycin; five of the isolates were also susceptible to ciprofloxacin and levofloxacin. All of the bacterial strains were resistant to erythromycin, oxacillin, and penicillin. The cutaneous MRSA infections persisted or worsened in the six athletes who were empirically treated for methicillin-sensitive S. aureus at their initial visit. Complete resolution of the skin infection occurred after the abscesses had been drained and the athlete had been treated with systemic antimicrobial therapy for which the bacterial strain was susceptible.

CONCLUSIONS

Cutaneous CAMRSA infection typically presents as an abscess, with or without surrounding cellulitis, in otherwise healthy participants of athletic activities who have or do not have MRSA-associated risk factors. Athletes who have MRSA skin infections include weight lifters and team members from competitive sports such as basketball, fencing, football, rugby, volleyball, and wrestling. Bacterial culture of suspected infectious skin lesions should be performed to establish the diagnosis of cutaneous MRSA infection and to determine the antibiotic susceptibility of the bacterial isolate. Treatment of cutaneous MRSA infection involves drainage of the abscess (either spontaneously or after incision) and appropriate systemic antimicrobial therapy. Direct skin-to-skin physical contact with infectious lesions or drainage, skin damage that facilitates the entry of bacteria, and sharing of infected equipment, clothing, or personal items may result in the acquisition and transmission of MRSA infection in participants of athletic activities. Earlier detection and topical treatment of the athlete's skin wounds by their coaches, avoidance of contact with other participants' cutaneous lesions and their drainage, and good personal hygiene are measures that can potentially prevent the spread of cutaneous MRSA infection in participants of athletic activities.

Physical and social home environment in relation to children's overall and home-based physical activity and sedentary time

BACKGROUND

Given the obesity epidemic, it is critical to understand factors associated with youth physical activity and sedentary behavior at home, where youth spend significant time. We examined relationships between these child behaviors and home environment factors.

METHODS

Data were obtained from 713 children aged 6 to 11 in Washington and California 2007-2009. Multivariate regression analyses controlling for socio-demographics examined associations between parent-reported home environment factors and child's accelerometer-measured moderate-to-vigorous physical activity (MVPA) and sedentary time, overall and at home, and parent-reported child screen time.

RESULTS

Children averaged 47.2% of time at home, which included 43.6% and 46.4% of overall MVPA and sedentary behavior, respectively. Parental support for physical activity and having a basketball hoop were positively associated with MVPA and negatively associated with sedentary behavior. Combined parental support and a basketball hoop was associated with even higher MVPA. Children with fewer bedroom media devices and more fixed play equipment had lower overall sedentary behavior and screen time than either factor alone. Findings were similar regardless of weight status.

CONCLUSIONS

Physical and social home environment variables, especially when combined, were related to more child MVPA and less sedentary behavior. Results support addressing multiple home environment factors in childhood obesity prevention.

An application of the matching law to evaluate the allocation of two- and three-point shots by college basketball players

We applied the matching equation to evaluate the allocation of two- and three-point shots by male and female college basketball players from a large Division 1 university. The matching law predicts that the proportion of shots taken from three-point range should match the proportional reinforcement rate produced by such shots. Thus, we compared the proportion of three-point shots taken relative to all shots to the proportion of three-point shots scored relative to all shots scored. However, the matching equation was adjusted to account for the greater reinforcer magnitude of the three-point basket (i.e., 1.5 times greater than the two-point basket reinforcer magnitude). For players with substantial playing time, results showed that the overall distribution of two- and three-point shots was predicted by the matching equation. Game-by-game shot distribution was variable, but the cumulative proportion of shots taken from three-point range as the season progressed was predicted almost perfectly on a player-by-player basis for both male and female basketball players.

Team cohesion and team success in sport

The main aim of this study was to examine the relationship between task cohesiveness and team success in elite teams using composite team estimates of cohesion. A secondary aim was to determine statistically the consistency (i.e. 'groupness') present in team members' perceptions of cohesion. Elite university basketball teams (n = 18) and club soccer teams (n = 9) were assessed for cohesiveness and winning percentages. Measures were recorded towards the end of each team's competitive season. Our results indicate that cohesiveness is a shared perception, thereby providing statistical support for the use of composite team scores. Further analyses indicated a strong relationship between cohesion and success (r = 0.55-0.67). Further research using multi-level statistical techniques is recommended.