The Effect of Shoulder Plyometric Training on Amortization Time and Upper-Extremity Kinematics.

Context: Plyometric training is credited with providing benefits in performance and dynamic restraint. However, limited prospective data exist quantifying kinematic adaptations such as amortization time, glenohumeral rotation, and scapulothoracic position, which may underlie the efficacy of plyometric training for upper-extremity rehabilitation or performance enhancement.

Objective: To measure upper-extremity kinematics and plyometric phase times before and after an 8-wk upper-extremity strength- and plyometric-training program.

Assessment of subacromial space and its relationship with scapular upward rotation in college baseball players.

Context: Subacromial impingement is a common injury in baseball players and has been linked to a reduction in the subacromial space. In addition, it has been suggested that decreases in scapular upward rotation will lead to decreases in the subacromial space and ultimately impingement syndrome.

Objective: The objective of this study was to evaluate the relationship between acromiohumeral distance and scapular upward rotation in healthy college baseball players.

Change in glenohumeral rotation and scapular position after a Division I collegiate baseball season.

Context: Pathologies such as anterior instability and impingement are common in baseball and have been linked to decreases in internal-rotation (IR) motion and concurrent increases in external-rotation (ER) motion. In addition, alterations to scapular upward rotation have been identified in this population.

Objective: To measure glenohumeral (GH) IR and ER rotation, total range of motion (ROM), and scapular upward rotation throughout the course of a Division I collegiate baseball season.

Neuromuscular and stiffness adaptations in division I collegiate baseball players.

To compare bi-lateral shoulder EMG, active and short range glenohumeral stiffness, and examine its correlation to posterior capsule thickness (PCT) in collegiate baseball players. Surface and fine wire EMG was recorded on shoulder and scapular musculature during stiffness testing. Posterior capsule thickness was assessed separately using a diagnostic ultrasound.

Rotator-cuff muscle-recruitment strategies during shoulder rehabilitation exercises.

Context: There are contradictory data on optimal muscle-activation strategies for restoring shoulder stability. Further investigation of neuromuscular-control strategies for glenohumeral-joint stability will guide clinicians in decisions regarding appropriate rehabilitation exercises.

Objectives: To determine whether subscapularis, infraspinatus, and teres minor (anteroposterior force couple) muscle activation differ between 4 shoulder exercises and describe coactivation ratios and individual muscle-recruitment characteristics of rotator-cuff muscles throughout each shoulder exercise.

Humeral retroversion and its association with posterior capsule thickness in collegiate baseball players.

Hypothesis And Background: Baseball players commonly present with decreases in internal rotation (IR) and concurrent increases in external rotation (ER) motion. Several glenohumeral (GH) adaptations have been theorized to cause these changes in motion, including humeral retroversion (HR) and posterior capsule thickness (PCT). However, limited data exist examining the inter-relationship between HR and PCT.

A bilateral comparison of posterior capsule thickness and its correlation with glenohumeral range of motion and scapular upward rotation in collegiate baseball players.

Hypothesis: We hypothesized that posterior capsule thickness (PCT) would be greater on the dominant arm compared to the non-dominant arm. We also hypothesized that PCT would negatively correlate with glenohumeral internal rotation and scapular upward rotation. In addition, PCT would positively correlate with glenohumeral external rotation.

Change in glenohumeral rotation and scapular position after competitive high school baseball.

Context: Pathologies such as anterior instability and impingement are common in baseball and have been linked to decreases in internal rotation (IR) and concurrent increases in external rotation (ER). In addition, alterations to scapular position have been identified in this population, but the chronology of these adaptations is uncertain.

Objectives: To determine whether there is a change in range of motion and scapular position after a single baseball season.

Internal rotation and scapular position differences: a comparison of collegiate and high school baseball players.

Context: Conditions such as labral and rotator cuff injuries have been linked with decreases in glenohumeral internal-rotation and increases in external-rotation motion. Also, decreased glenohumeral internal rotation is strongly associated with scapular dyskinesis.

Objective: To compare healthy collegiate and high school baseball players' glenohumeral joint range of motion and scapular position.

Internal rotation deficits affect scapular positioning in baseball players.

Background: Anecdotal evidence suggests an association between glenohumeral internal rotation deficits (GIRD) and scapular dysfunction, an observable alteration in the normal position or motion of the scapula in relation to the thoracic cage.

Questions/purposes: We therefore hypothesized players with GIRD (15 degrees or greater) will have decreased dominant arm scapular upward rotation and increased scapular protraction compared with baseball players with GIRD (14 degrees or less).

Methods: We studied 43 baseball players with no current shoulder or elbow symptoms; 22 had GIRD 15 degrees or greater and 21 had GIRD 14 degrees or less.

Glenohumeral rotation and scapular position adaptations after a single high school female sports season.

Context: Anterior instability and impingement are common in overhead athletes and have been associated with decreases in internal rotation (IR) and increases in external rotation (ER) motion. However, the chronology and the effect of different female sports on these conditions have yet to be determined.

Objective: To measure glenohumeral IR and ER rotation, total range of motion, and scapular position in female overhead athletes over a single competitive season.

An electromyographic assessment of the "bear hug": an examination for the evaluation of the subscapularis muscle.

Purpose: The lift-off and belly-press tests are common tests for evaluation of the subscapularis. We compared these tests with the recently developed bear-hug test by assessing electromyographic (EMG) activity of the shoulder internal rotators during examination.

Methods: Twenty-one healthy male volunteers (mean age, 22.

Stiffness regulation and muscle-recruitment strategies of the shoulder in response to external rotation perturbations.

Background: The complex interactions between capsuloligamentous structures and muscle-recruitment strategies that maintain glenohumeral stability remain unclear. The purposes of the present study were to determine whether stiffness regulation and muscle-activation strategies differed under varying joint positions and levels of contraction in the shoulder and to determine the relationship between generalized joint laxity, glenohumeral joint laxity, and joint stiffness.

Methods: Forty healthy, physically active subjects with a mean age (and standard deviation) of 25.

High-risk drinking characteristics in collegiate athletes.

Objective: The authors aimed to further describe the relationship of alcohol use by college athletes to variables, such as sport participation, time of year, and level of competition.

Participants: There were 720 participants from Divisions I, II, and III who participated in either a team sport or an individual sport.

Methods: The authors measured characteristics of alcohol use by college athletes at 9 colleges and universities.

Resistance training and head-neck segment dynamic stabilization in male and female collegiate soccer players.

Context: Cervical resistance training has been purported to aid in reducing the severity of brain injuries in athletes.

Objective: To determine the effect of an 8-week resistance-training program on head-neck segment dynamic stabilization in male and female collegiate soccer players.

Design: Pretest and posttest control group design.

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.

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.

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.

Neuromuscular dynamic restraint in women with anterior cruciate ligament injuries.

The purpose of this study was to identify neuromuscular characteristics related to dynamic restraint in the knee. Observing compensatory changes to these characteristics in women with anterior cruciate ligament injuries provides important information for understanding functional knee stability, injury prevention, and performance. Twelve female subjects with anterior cruciate ligament injuries and 17 female control subjects participated in this study to assess electromyographic activity during landing from a hop and knee perturbation; hamstring muscle stiffness and flexibility; and isokinetic strength.

Effectiveness of Glenohumeral-Joint Stability Braces in Limiting Active and Passive Shoulder Range of Motion in Collegiate Football Players.

OBJECTIVE: To determine the effectiveness of glenohumeral-joint stability braces in limiting active and passive shoulder abduction and external rotation in collegiate football players. DESIGN AND SETTING: A 2-factor, repeated-measures design was used. The independent variables were brace condition (Denison and Duke Wyre harness, Sawa shoulder brace) and force application (active, passive).

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.

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.

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.