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Biomedical subjects

Paul A Borsa

Publications and source records attributed to Paul A Borsa.

12 recordsLinked to original sources
PubMed2006

Gender and limb differences in dynamic postural stability during landing.

OBJECTIVE: To determine if gender and limb dominance affect dynamic postural stability and vertical ground reaction force data during jump landings. Secondary objective was to assess the reliability of the dynamic postural stability index (DPSI). DESIGN: A mixed model (2 genderx2 limb) repeated measures design was used to determine the effects of gender and limb dominance on dynamic postural stability. Subjects were required to perform a two-legged jump to a height equivalent of 50% of their maximum vertical leap, land on a single-leg and balance for three seconds. SETTING: Sports Medicine Research Laboratory. PARTICIPANTS: Forty healthy subjects (20 men, 20 women) participated in this investigation. MAIN OUTCOME MEASURES: The DPSI and its directional components quantified dynamic postural stability during a single-leg jump landing. Normalized vertical ground reaction force data quantified energy absorption. RESULTS: DPSI values revealed that females had significantly different dynamic postural stability as compared to males in the vertical plane [T (78)=-4.2, P<0.01], and in the composite score (dynamic postural stability index) [T (78)=-6.3, P<0.01]. In addition, females had significantly higher peak vertical ground reaction forces [T (78)=-13, P=0.01] than males. The DPSI also showed excellent reliability (ICC=0.96), with a 95% confidence interval ranging from 0.94 to 0.97. CONCLUSIONS: The results indicate that females have higher dynamic postural stability scores in the vertical direction as well as the composite score. This suggests that females used different dynamic postural stability strategies than males. There were no side-to-side dynamic postural stability differences between healthy contralateral limbs.

Adult↗
PubMed2006

Glenohumeral range of motion and stiffness in professional baseball pitchers.

PURPOSE: This study was conducted to perform kinematic measures in a group of asymptomatic professional baseball pitchers to determine side-to-side differences in passive glenohumeral range of motion (ROM) and stiffness. We hypothesized that the throwing shoulder in asymptomatic pitchers would display greater passive glenohumeral stiffness than the contralateral nonthrowing shoulder. METHODS: Thirty-four professional baseball pitchers had bilateral assessments for passive glenohumeral ROM and stiffness during a single test session. ROM and stiffness measures were obtained objectively using standard goniometry and instrumented stress arthrometry, respectively. RESULTS: The throwing shoulder had significantly less (-8.5 degrees) internal rotation and significantly more external rotation (5.1 degrees) than the nonthrowing shoulder (P < 0.01). Passive joint stiffness was not significantly different between the throwing and nonthrowing shoulder, and anterior joint stiffness was significantly greater than posterior joint stiffness for both shoulders (P < 0.05). CONCLUSIONS: The repetitive stress of long-term throwing creates altered glenohumeral rotational patterns in the throwing shoulder of the professional baseball pitcher without compromising the joint's passive restraining quality.

Adult↗
PubMed2006

Measurement and evaluation of dynamic joint stability of the knee and ankle after injury.

Injuries to the lower extremity, specifically the knee and ankle joints of the human body can occur in any athletic event and are most prevalent in sports requiring cutting and jumping manoeuvres. These joints are forced to rely on the dynamic restraints to maintain joint stability, due to the lack of bony congruence and the inability of the static restraints to handle the forces generated during functional tasks. Numerous variables (proprioception, postural control, electromyography, kinetics/kinematics, dynamic stability protocols) have been measured to better understand how the body maintains joint stability during a wide range of activities from static standing to dynamic cutting or landing from a jump. While the importance of dynamic restraints is not questioned, a recent impetus to conduct more functional or sport-specific testing has emerged and placed a great deal of emphasis on dynamic joint stability and how it is affected by lower extremity injuries. Evidence suggests that surgery and aggressive rehabilitation will not necessarily restore the deficits in dynamic joint stability caused by injury to the anterior cruciate ligament or lateral ankle ligaments. In today's athletic society, there is a major push to return athletes to play as quickly as possible. However, the ramifications of those decisions have not been fully grasped. If an athlete is not fully recovered, a quick return to play could start a vicious cycle of chronic injuries or permanent disability.

Ankle Injuries↗
PubMed2005

Correlation of range of motion and glenohumeral translation in professional baseball pitchers.

BACKGROUND: Altered mobility patterns in the throwing shoulders of professional baseball pitchers have been reported. Most published reports examining glenohumeral laxity have not used an objective testing device. OBJECTIVE: Quantify and compare glenohumeral translation and rotational range of motion between the throwing and non-throwing shoulders in professional baseball pitchers. STUDY DESIGN: Descriptive laboratory study. METHODS: Force-displacement and range of motion measures were performed bilaterally on 43 asymptomatic professional baseball pitchers. Ultrasound imaging was used to measure glenohumeral translations under stressed and unstressed conditions. RESULTS: No significant difference in translation was found between the throwing and nonthrowing shoulders. For both shoulders, posterior translation (5.38 +/- 2.7 mm) was significantly greater (P < .001) than was anterior translation (2.81 +/- 1.6 mm). External rotation in the throwing shoulder was significantly greater than that in the nonthrowing shoulder (P < .001), whereas internal rotation in the throwing shoulder was significantly less than that in the nonthrowing shoulder (P < .001). The total arc of rotation for the throwing shoulder was not significantly different than that for the nonthrowing shoulder, and correlation coefficients were poor between rotational and translational range of motion in the throwing shoulder, ranging from r = 0.232 to 0.209 between variables. CONCLUSION: No significant difference in glenohumeral translation exists between the throwing and nonthrowing shoulders in asymptomatic professional baseball pitchers, posterior translation is significantly greater than anterior translation in the throwing shoulders of professional baseball pitchers, and glenohumeral translation is not related to rotational range of motion in the throwing shoulders of professional baseball pitchers. CLINICAL RELEVANCE: Altered mobility patterns in asymptomatic professional baseball pitchers may be due to factors other than capsular adaptive changes.

Adult↗
PubMed2005

Comparison of dynamic sonography to stress radiography for assessing glenohumeral laxity in asymptomatic shoulders.

BACKGROUND: Stress radiography has been the established imaging method for quantifying glenohumeral joint laxity. Dynamic ultrasound is an alternative imaging method that may be used to measure glenohumeral laxity; however, validity and repeatability have not been examined. OBJECTIVE: To determine criterion-related validity and repeatability of a sonographic imaging method for measuring glenohumeral laxity in asymptomatic shoulders. STUDY DESIGN: Controlled laboratory study. METHODS: In experiment 1, 20 subjects were assessed for glenohumeral laxity using stress radiography and dynamic ultrasound. In the second experiment, 13 subjects were assessed for laxity in 2 separate test sessions using the dynamic ultrasound technique. RESULTS: Correlational analysis between the sonographic and radiographic measures revealed an r = 0.79 (r(2) = 0.62), indicating excellent criterion-related validity for the sonographic imaging method. Test-retest repeatability was 0.72 and 0.85 for anterior and posterior translation, respectively, and interrater repeatability was 0.96 and 0.99 for anterior and posterior translation, respectively. CONCLUSIONS: Dynamic ultrasound appears to be a valid and repeatable method for assessing glenohumeral laxity in a clinical setting. CLINICAL RELEVANCE: Based on the results of this study, dynamic ultrasound is a repeatable and valid method for measuring glenohumeral laxity and therefore may be used as a viable replacement for stress radiography during assessments of glenohumeral laxity.

Adult↗
PubMed2005

Sonographic stress measurement of glenohumeral joint laxity in collegiate swimmers and age-matched controls.

BACKGROUND: Glenohumeral laxity that is greater than normal has been implicated as a causal factor in the development of shoulder pain and dysfunction in elite swimmers; however, quantitative evidence demonstrating greater-than-normal glenohumeral joint laxity in swimmers is lacking. OBJECTIVE: To quantify glenohumeral joint laxity in elite swimmers and nonswimming controls using stress sonography. STUDY DESIGN: Controlled laboratory study. METHODS: Force-displacement measures were performed bilaterally in 42 National Collegiate Athletic Association Division I swimmers and 44 age-matched controls. Of the 42 swimmers, 27 (64%) reported a history of unilateral or bilateral shoulder pain resulting from swimming. Ultrasound imaging was used to measure glenohumeral joint displacement under stressed and non-stressed conditions. RESULTS: An analysis of variance revealed no significant difference in glenohumeral joint displacement between swimmers (anterior, 2.82 +/- 1.7 mm; posterior, 5.30 +/- 2.4 mm) and age-matched controls (anterior, 2.74 +/- 1.7 mm; posterior, 4.90 +/- 2.7 mm). No significant difference in glenohumeral joint displacement was found between swimmers with a history of shoulder pain (anterior, 2.90 +/- 1.6 mm; posterior, 5.42 +/- 2.3 mm) versus swimmers without a history of shoulder pain (anterior, 2.74 +/- 1.8 mm; posterior, 5.14 +/- 2.6 mm). Shoulders displayed significantly more glenohumeral joint displacement in the posterior direction compared to the anterior direction (P < .001). CONCLUSIONS: Our instrumented technique was unable to identify significantly greater glenohumeral joint displacement in elite swimmers compared to nonswimming controls, and elite swimmers with a history of shoulder pain were not found to have significantly more glenohumeral joint displacement compared to swimmers without a history of shoulder pain. CLINICAL RELEVANCE: Objective assessment of glenohumeral joint displacement in athletes participating in overhead-motion sports may be important for injury prevention and management.

Adult↗
PubMed2005

Detection of dynamic stability deficits in subjects with functional ankle instability.

PURPOSE: To determine which combination of landing protocol and analysis technique would be the most effective at detecting differences in dynamic stability between healthy subjects and subjects with functional ankle instability (FAI). METHODS: Fifty-eight subjects participated in this investigation: 29 healthy individuals and 29 individuals with FAI. Subjects were assessed during a single test session for time to stabilization (TTS) in the anterior/posterior, medial/lateral, and vertical directions from two protocols: a step down and jump protocol. The step down protocol started with each subject atop a 20-cm-high platform, and the jump protocol started with subjects in a standing position 70 cm from the center of a force plate and required each subject to jump off both legs and touch a designated marker placed at a position equivalent to 50% of the subject's maximum vertical leap. TTS scores in the anterior/posterior, medial/lateral, and vertical direction were compared between group, protocol, and type of analysis. RESULTS: A significant protocol by analysis by group interaction (F(1,56) = 6.9, P = 0.011) was observed for anterior/posterior TTS. Likewise, protocol by group (F(1,56) = 4.4, P = 0.042) and protocol by analysis (F(1,56) = 14.1, P < 0.001) interactions were also noted in anterior/posterior TTS. The jump protocol (2381.7 +/- 36.5 ms) produced significantly greater TTS scores in the vertical direction than the step protocol (1533.5 +/- 71.8 ms), whereas the unbounded third order polynomial (UTOP) method (2554.4 +/- 68.7 ms) produced significant greater TTS scores as compared with the sequential estimation (SE) method (1360.8 +/- 52.1 ms). CONCLUSIONS: The jump protocol and UTOP method of analysis are the most effective TTS combination in detecting differences between healthy and FAI groups.

Adult↗
PubMed2002

Glenohumeral Stiffness Response Between Men and Women for Anterior, Posterior, and Inferior Translation.

OBJECTIVE: To quantify and compare the glenohumeral stiffness response in anterior-directed, posterior-directed, and inferior-directed translations in healthy men and women. DESIGN AND SETTING: We used a 2 division on times 3 factorial design and employed a device capable of measuring glenohumeral joint displacement as a function of force to gather kinematic data during a single test session. SUBJECTS: Twenty subjects with healthy nondominant shoulders participated in the study. MEASUREMENTS: Force-displacement measures were taken in the anterior, posterior, and inferior translational directions of the glenohumeral joint. These measurements simulated common laxity tests used at the shoulder. RESULTS: Analysis of variance revealed a nonsignificant sex division on times direction interaction effect (P >.05). The main effect for sex and direction was also not significant (P >.05). CONCLUSIONS: Our results suggest that (1) glenohumeral stiffness is widely distributed in healthy shoulders, (2) glenohumeral stiffness is not significantly different between men and women, and (3) glenohumeral stiffness is not significantly different among directions of translations.

Journal Article↗
PubMedDate not supplied

A new force-plate technology measure of dynamic postural stability: the dynamic postural stability index.

CONTEXT: New measures of dynamic postural stability are needed to address weaknesses of previous measures. OBJECTIVE: To assess the feasibility, reliability, and precision of a new measure of dynamic postural stability. DESIGN: A single within-subjects design was used to determine optimal sampling interval as well as intersession reliability. SETTING: Biomechanics laboratory. PATIENTS OR OTHER PARTICIPANTS: Eighteen subjects (7 men [age = 22 +/- 3 years, height = 175 +/- 5 cm, mass = 75 +/- 16 kg] and 11 women [age = 23 +/- 2 years, height = 163 +/- 6 cm, mass = 68 +/- 13 kg]) without lower extremity impairment. INTERVENTION(S): A jump protocol that required subjects to perform a 2-legged jump to a height equivalent to 50% of their maximum vertical leap and land on a single leg. MAIN OUTCOME MEASURE(S): The Dynamic Postural Stability Index (DPSI) and the directional components (medial-lateral, anterior-posterior, and vertical) after a jump landing. RESULTS: We observed a significant sampling-interval main effect (F(2,51) = 26.88, P < .01) for the DPSI; the 10-second trial duration produced significantly smaller means than the 5- and 3-second trial durations, whereas the 5-second trial result was also significantly smaller than that of the 3-second trial. The DPSI was highly reliable between test sessions (intraclass correlation coefficient = .96) and very precise (SEM = .03). CONCLUSIONS: These results suggest that the DPSI can be used in conjunction with a functional single-leg hop stabilization test and is a reliable and precise measure of dynamic postural stability. We believe the shortest sampling interval (3 seconds) is the best choice for studying and mimicking athletic performance as closely as possible.

Journal Article↗
PubMedDate not supplied

Dynamic postural stability in subjects with braced, functionally unstable ankles.

CONTEXT: Research concerning prophylactic ankle stabilizers (PASs) has focused on healthy subjects, and the results cannot be generalized to the functional ankle instability (FAI) population, a population that has an increased risk of reinjury and is likely to wear PASs. OBJECTIVE: To determine whether PASs improve dynamic postural stability in FAI subjects as compared with a control (no-brace) condition. DESIGN: A crossover design was used to determine the effects of PASs on dynamic postural stability and vertical ground reaction forces. SETTING: Biomechanics laboratory. PATIENTS OR OTHER PARTICIPANTS: Twenty-eight subjects with unilateral FAI, 13 men (age = 21.5 +/- 1.2 years, height = 181.5 +/- 10.5 cm, mass = 77.6 +/- 17.2 kg) and 15 women (age = 20.5 +/- 1.1 years, height = 169.4 +/- 8.2 cm, mass = 67.9 +/- 8.8 kg). INTERVENTION(S): A jump protocol required subjects to perform a 2-legged jump to a height equivalent to 50% of their maximum vertical leap and land on a single leg. MAIN OUTCOME MEASURE(S): The dynamic postural stability index, the directional components (medial-lateral, anterior-posterior, and vertical), and vertical ground reaction force after a jump landing. RESULTS: Compared with the control condition, only the vertical component score was reduced (improved) with the application of a soft or semirigid PAS (P < .01). CONCLUSIONS: Soft and semirigid PASs did not improve dynamic postural stability as measured by the Dynamic Postural Stability Index. However, PASs may help with the attenuation of vertical forces.

Journal Article↗