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Biomedical subjects

C Buz Swanik

Publications and source records attributed to C Buz Swanik.

11 recordsLinked to original sources
PubMed2006

Gender comparisons of dynamic restraint and motor skill in children.

OBJECTIVES: To assess differences in neuromuscular dynamic restraint between high-skilled and low-skilled prepubescent girls and boys. To determine the contribution of sport experience and physical characteristics to motor skill. SUBJECTS: Nineteen girls and 17 boys (8.89-9.40 y) participated. INTERVENTION: Isometric hamstring and quadriceps muscle strength was assessed. Subjects performed 3 landing trials for measurement of preparatory EMG and vertical leg stiffness. Motor skill was assessed through analysis of 12 fundamental tasks. Sport experience was reported as hours per week and total years in organized and nonorganized activity. OUTCOME MEASURES: Dynamic restraint variables of isometric strength, preparatory EMG activity, and vertical leg stiffness were measured between groups. The contributions of time in sport, type of sport, and physical characteristics on skill were analyzed. RESULTS: No significant gender or skill differences were found in quadriceps strength (P = 0.73), hamstring strength (P = 0.96), hamstring-to-quadriceps ratio (P = 0.71), or vertical leg stiffness (P = 0.38). Low-skilled children exhibited significantly greater (47.8%) preparatory hamstring-quadriceps coactivation than high-skilled subjects (P = 0.03). Participation in organized and nonorganized sport accounted for 29% of the variance in motor skill. CONCLUSIONS: Neuromuscular differences between genders were not observed, but dynamic restraint EMG measures differed between skill levels. The factors predisposing females to noncontact injuries may develop prepuberty to postpuberty from a combination of variables. Greater coactivation in the low-skilled group appears consistent with immature feedforward neuromuscular control strategies. These unrefined motor skills are less economical, may compromise dynamic restraint, and appear partially determined by sport experience.

Athletic Injuries↗
PubMed2005

Gender differences in head-neck segment dynamic stabilization during head acceleration.

PURPOSE: Recent epidemiological research has revealed that gender differences exist in concussion incidence but no study has investigated why females may be at greater risk of concussion. Our purpose was to determine whether gender differences existed in head-neck segment kinematic and neuromuscular control variables responses to an external force application with and without neck muscle preactivation. METHODS: Forty (20 females and 20 males) physically active volunteers participated in the study. The independent variables were gender, force application (known vs unknown), and force direction (forced flexion vs forced extension). The dependent variables were kinematic and EMG variables, head-neck segment stiffness, and head-neck segment flexor and extensor isometric strength. Statistical analyses consisted of multiple multivariate and univariate analyses of variance, follow-up univariate analyses of variance, and t-tests (P < or = 0.05). RESULTS: Gender differences existed in head-neck segment dynamic stabilization during head angular acceleration. Females exhibited significantly greater head-neck segment peak angular acceleration (50%) and displacement (39%) than males despite initiating muscle activity significantly earlier (SCM only) and using a greater percentage of their maximum head-neck segment muscle activity (79% peak activity and 117% muscle activity area). The head-neck segment angular acceleration differences may be because females exhibited significantly less isometric strength (49%), neck girth (30%), and head mass (43%), resulting in lower levels of head-neck segment stiffness (29%). CONCLUSION: For our subject demographic, the results revealed gender differences in head-neck segment dynamic stabilization during head acceleration in response to an external force application. Females exhibited significantly greater head-neck segment peak angular acceleration and displacement than males despite initiating muscle activity earlier (SCM only) and using a greater percentage of their maximum head-neck segment muscle activity.

Acceleration↗
PubMed2005

Joint stiffness and pain in individuals with patellofemoral syndrome.

STUDY DESIGN: Pretest-posttest matched control group design. OBJECTIVES: To measure passive knee joint stiffness and pain in participants with and without patellofemoral pain syndrome (PFPS) and to determine the relationship between mechanical knee joint stiffness, self-reported stiffness, and pain. BACKGROUND: Patients with PFPS complain of knee joint stiffness and pain, but no research has quantified both of these characteristics in this population. METHODS AND MEASURES: Twenty-eight individuals (14 with PFPS [mean age +/- SD, 25.5 +/- 4.8 years] and 14 healthy controls [mean age +/- SD, 22.8 +/- 5.4 years]) volunteered for this study. Mechanical passive knee joint stiffness was calculated using the damped natural frequency of oscillation of the lower leg while sitting. Mechanical stiffness was compared to self-reports of knee stiffness and pain. All measurements were recorded presitting and after 20 minutes of sitting. RESULTS: Sitting for 20 minutes did not induce significant changes in mechanical knee joint stiffness. However, participants with PFPS reported significantly greater (P<.01) knee stiffness after sitting for 20 minutes. A significant correlation (r = 0.70, P<.01) was found between self-reported stiffness and pain in participants with PFPS; however, no significant relationship was observed between mechanical and self-reported knee joint stiffness. CONCLUSIONS: Despite frequent complaints of joint stiffness, the knees of individuals with PFPS do not appear physiologically stiffer than those of control subjects. Individuals with PFPS perceive increased knee stiffness after sitting, but may misinterpret the sensation of pain as joint stiffness.

Adult↗
PubMed2004

Proprioception, kinesthesia, and balance after total knee arthroplasty with cruciate-retaining and posterior stabilized prostheses.

BACKGROUND: The effect of total knee arthroplasty on proprioception, kinesthesia, and postural control remains controversial. It is argued that retaining the posterior cruciate ligament may help to preserve these sensorimotor functions and improve the longevity of the prosthesis and the functional outcome. We performed a prospective, randomized study to assess proprioception, kinesthesia, and balance following total knee arthroplasty with cruciate-retaining and posterior stabilized prostheses. METHODS: Twenty patients scheduled to undergo total knee arthroplasty were randomly assigned to receive either a cruciate-retaining or a posterior stabilized prosthesis. Joint-position sense, the threshold to detect joint motion, and the subject's ability to balance on an unstable platform were assessed prior to and at least six months after the operation. Paired two-tailed t tests (with a level of significance of p < 0.05) were used to assess the effect of the arthroplasty on the preoperative measures for all subjects. Analysis of covariance was performed to identify the effects of prosthetic design. RESULTS: Following total knee arthroplasty, patients detected motion significantly faster and reproduced joint position with less error. The balance index also improved significantly from the preoperative to the postoperative evaluation. The group treated with the posterior stabilized prosthesis more accurately reproduced joint position when the knee was extended from a flexed position. CONCLUSIONS: Total knee arthroplasty results in mild improvements in proprioception, kinesthesia, and balance. These changes may result from the retensioned capsuloligamentous structures and reduced pain and inflammation. Retention of the posterior cruciate ligament does not appear to significantly improve proprioception and balance compared with those functions in patients with a posterior stabilized total knee design.

Aged↗
PubMed2004

Effects of Plyometric Training on Muscle-Activation Strategies and Performance in Female Athletes.

OBJECTIVE: To evaluate the effects of plyometric training on muscle-activation strategies and performance of the lower extremity during jumping exercises. SUBJECTS: Twenty healthy National Collegiate Athletic Association Division I female athletes. DESIGN AND SETTING: A pretest and posttest control group design was used. Experimental subjects performed plyometric exercises 2 times per week for 6 weeks. MEASUREMENTS: We used surface electromyography to assess preparatory and reactive activity of the vastus medialis and vastus lateralis, medial and lateral hamstrings, and hip abductors and adductors. Vertical jump height and sprint speed were assessed with the VERTEC and infrared timing devices, respectively. RESULTS: Multivariate analyses of variance revealed significant (P <.05) increases in firing of adductor muscles during the preparatory phase, with significant interactions for area, mean, and peak. A Tukey honestly significant difference post hoc analysis revealed significant increases in preparatory adductor area, mean, and peak for experimental group. A significant (P =.037) increase in preparatory adductor-to-abductor muscle coactivation in the experimental group was identified, as well as a trend (P =.053) toward reactive quadriceps-to- hamstring muscle coactivation in the experimental group. Pearson correlation coefficients revealed significant between-groups adaptations in muscle activity patterns pretest to posttest. Although not significant, experimental and control subjects had average increases of 5.8% and 2.0% in vertical jump height, respectively. CONCLUSIONS: The increased preparatory adductor activity and abductor-to-adductor coactivation represent preprogrammed motor strategies learned during the plyometric training. These data strongly support the role of hip-musculature activation strategies for dynamic restraint and control of lower extremity alignment at ground contact. Plyometric exercises should be incorporated into the training regimens of female athletes and may reduce the risk of injury by enhancing functional joint stability in the lower extremity.

Journal Article↗
PubMed2003

Epidemiological considerations of concussions among intercollegiate athletes.

The purpose of this study was to examine epidemiological trends of concussions among 15 different intercollegiate sports during the 1997-1998, 1998-1999, and 1999-2000 seasons. Data were collected using the National Collegiate Athletic Association (NCAA) Injury Surveillance System (ISS). For the 15 sports studied during the 3 academic years, the NCAA ISS documented 3,535 team-seasons, 40,547 reportable injuries, 5,566,924 practice athlete exposures (AEs), and 1,090,298 game AEs. Concussions accounted for 6.2% of all reported injuries during this 3-year study. Of all the reported injuries, women lacrosse players (13.9%) reported the highest percentage of suffering a concussion during a game followed by women's soccer (11.4%), men's ice hockey (10.3%), men's lacrosse (10.1%), football (8.8%), women's basketball, (8.5%), field hockey (7.2%), men's soccer (7.0%), wrestling (6.6%), men's basketball (5.0%), baseball (4.2%), and women's volleyball (4.1%). Female athletes from all 7 sports were found to be at a lower risk for suffering concussions during practice sessions than the 8 male sports. However, female athletes were found to be at a greater risk for suffering concussions during games compared to male athletes. Injury trends over the 3- year period indicate concussions continue to be on the rise for athletes participating in collegiate football, men's soccer, and women's and men's basketball.

Adult↗
PubMed2003

Effects of Football Collars on Cervical Hyperextension and Lateral Flexion.

OBJECTIVES: To evaluate the effectiveness of 3 football collars in reducing cervical range of motion. DESIGN AND SETTING: A repeated-measures design in a controlled laboratory setting. SUBJECTS: Fifteen male National Collegiate Athletic Association Division I varsity football athletes. MEASUREMENTS: Cervical hyperextension and lateral flexion were measured with video analysis. Subjects underwent 5 testing conditions: standard football helmet, standard helmet and shoulder pads, and standard pads with the addition of the Cowboy Collar, A-Force Neck Collar, or a foam neck roll. Subjects performed motions both actively and passively. RESULTS: All 3 collars reduced hyperextension when compared with the helmet and shoulder pads alone (P <.05); in addition, the Cowboy Collar was superior to the foam neck roll (P <.05) in reducing hyperextension. No collar reduced passive lateral flexion when compared with the helmet and shoulder pads, but the foam neck roll permitted significantly less active lateral flexion (P <.01) than the other 3 brace conditions. CONCLUSIONS: In a laboratory setting, cervical hyperextension can be controlled through the use of various cervical collars. Cervical lateral flexion (a more common cause of burners in a scholastic population) cannot be controlled with any of the cervical collars tested. Moreover, foam collars may impede active lateral flexion while not providing additional protection when loaded. These results are limited in that they were produced in a controlled situation as opposed to active football play.

Journal Article↗
PubMed2003

Sex Differences and the Incidence of Concussions Among Collegiate Athletes.

OBJECTIVE: To compare sex differences regarding the incidence of concussions among collegiate athletes during the 1997-1998, 1998-1999, and 1999-2000 seasons. DESIGN AND SETTING: A cohort study of collegiate athletes using the National Collegiate Athletic Association (NCAA) Injury Surveillance System; certified athletic trainers recorded data during the 1997-2000 academic years. SUBJECTS: Collegiate athletes participating in men's and women's soccer, lacrosse, basketball, softball, baseball, and gymnastics. MEASUREMENTS: Certified athletic trainers from participating NCAA institutions recorded weekly injury and athlete-exposure data from the first day of preseason practice to the final postseason game. Injury rates and incidence density ratios were computed. Incidence density ratio is an estimate of the relative risk based on injury rates per 1000 athlete-exposures. RESULTS: Of 14 591 reported injuries, 5.9% were classified as concussions. During the 3-year study, female athletes sustained 167 (3.6%) concussions during practices and 304 (9.5%) concussions during games, compared with male athletes, who sustained 148 (5.2%) concussions during practices and 254 (6.4%) concussions during games. Chi-square analysis revealed significant differences between male and female soccer players (chi(2)(1) = 12.99, P =.05) and basketball players (chi(2)(1) = 5.14, P =.05). CONCLUSIONS: Female athletes sustained a higher percentage of concussions during games than male athletes. Of all the sports, women's soccer and men's lacrosse were found to have the highest injury rate of concussions. Incidence density ratio was greatest for male and female soccer players.

Journal Article↗
PubMedDate not supplied

The effects of shoulder plyometric training on proprioception and selected muscle performance characteristics.

The purpose of this study was to determine the effect of plyometric training of the shoulder internal rotators on proprioception, kinesthesia, and selected muscle performance characteristics in female swimmers. Twenty-four female division I swimmers were evaluated before and after a 6-week plyometric training program. Proprioception and kinesthesia were assessed for internal and external rotation at 0 degrees, 75 degrees, and 90% of the subject's maximum external rotation. The Biodex II was used to assess strength characteristics at 60 degrees /s, 240 degrees /s, and 450 degrees /s. Plyometric training sessions (2 times/week) involved 3 sets of 15 repetitions with a trampoline, weighted balls, and elastic tubing. A 2-way analysis of variance revealed significant improvement (P <.05) in proprioception at 0 degrees moving into external rotation, as well as 75 degrees and 90% moving into both internal and external rotation. Kinesthesia demonstrated significant improvement for all test conditions after plyometric training. Significant gains in selected muscle performance characteristics included time to peak torque (60 degrees /s and 240 degrees /s), amortization time (450 degrees /s), and torque decrement (240 degrees /s). This study suggests that plyometric activities may facilitate neural adaptations that enhance proprioception, kinesthesia, and muscle performance characteristics. Significant neuromuscular benefits may be attained if they are implemented earlier into shoulder rehabilitation programs.

Adult↗
PubMedDate not supplied

Effects of sport massage on limb girth and discomfort associated with eccentric exercise.

CONTEXT: Sport massage is often used to help prepare for exercise, expedite recovery from muscle soreness, and enhance athletic performance. However, the effect of sport massage on recovery from delayed-onset muscle soreness is unknown. OBJECTIVE: To determine the effect of a short sport massage treatment on intramuscular swelling and pain in response to eccentric exercise. DESIGN: We used a 2 x 8 (treatment x time) repeated-measures design to compare triceps surae muscle girth and pain ratings over the 72 hours after eccentric exercise. SETTING: University research laboratory. PATIENTS OR OTHER PARTICIPANTS: Nineteen healthy, college-aged subjects. INTERVENTION(S): Delayed-onset muscle soreness was induced with several sets of eccentric triceps surae contractions at 90% of the estimated concentric, 1-repetition maximum weight. Subjects returned on 3 consecutive days after eccentric exercise with a cycle ergometer for active rest treatments. In addition, 1 leg received the sport massage. MAIN OUTCOME MEASURE(S): Girth measurements were taken at 5.08 cm (2 in), 10.16 cm (4 in), 15.24 cm (6 in), and 20.32 cm (8 in) below the knee joint line, and pain was assessed with a visual analog scale before and after all 4 sessions. RESULTS: No interaction was noted between treatment and time for any girth or pain measurements, and no main effect was seen for treatment. CONCLUSIONS: Sport massage did not reduce girth or pain in the lower leg after eccentric exercise within 72 hours.

Journal Article↗