J Orthop Sports Phys Ther 1989;10(12):495-498.

J Orthop Sports Phys Ther 1992;16(4):174-181.

Key Words: ACL insufficient, assessment, function

Single leg hop tests are commonly used as physical performance measures of function and are also commonly used to evaluate progress in knee rehabilitation programs, particularly for individuals recovering from anterior cruciate ligament injury or reconstructive surgery. While there is some evidence that hop tests may show promise as a predictive measure for identifying individuals who are at risk for recurrent dynamic instability, further work is needed to clearly define the role of hop test measurements for this purpose. The purposes of this clinical commentary are to review the research that has been done to establish hop tests as a physical performance measure of function, to discuss neuromuscular and biomechanical considerations related to hop performance and dynamic knee stability, to discuss existing evidence that supports the potential for hop tests as a predictor of dynamic knee stability, and to discuss considerations for future studies that are designed to more clearly define the role of hop tests in predicting dynamic knee stability.

J Orthop Sports Phys Ther. 200l;31(10):588-597.

Key Words: anterior cruciate ligament, functional performance testing, hop tests

Study Design: A nonrandomized 2-group pretest-posttest design. Objectives: To determine the effects of a 4-week balance training program during stance on a single leg. Background: Individuals who have experienced multiple episodes of inversion ankle sprains often participate in balance training programs. Balance training is performed to treat existing proprioceptive deficits and to restore ankle joint stability, presumably by retraining altered afferent neuromuscular pathways. The effectiveness of such programs on individuals with functionally unstable ankles has yet to be established. Methods and Measures: Prior to and following training, subjects with self-reported functionally unstable ankles (5 women and 8 men, mean age = 21.9 ± 3.1 years) and nonimpaired subjects (6 women and 7 men, mean age = 21.2 ± 2.5 years) completed a static balance assessment for both limbs as well as the ankle joint functional assessment tool questionnaire (AJFAT). The subjects from both groups participated in a unilateral, multilevel, static and dynamic balance training program 3 times a week for 4 weeks. Subjects from the experimental group trained only the involved limb, and the nonimpaired group trained a randomly selected limb. A stability index (SI) was calculated during the balance assessment to indicate the amount of platform motion. Compared to low stability indices, high stability indices indicate greater platform motion during stance and therefore less stability. Results: Following training, subjects from both groups demonstrated significant improvements in balance ability. When balance was assessed at a low resistance to platform tilt (stability level 2), the posttraining scores of both the subjects with unstable ankles (mean SI = 2.63 ± 1.92) and the nonimpaired subjects (mean SI = 2.69 ± 2.32) were significantly better than their pretraining scores (mean Sls = 5.93 ± 3.65 and 4.67 ± 3.43, respectively). Assessed at a high resistance to platform tilt (stability level 6), the posttraining scores of both subjects with unstable ankles (mean SI = 1.27 ± 0.66) and the nonimpaired subjects (mean SI = 1.37 ± 0.66) were significantly better than their pretraining scores (mean Sls = 2.30 ± 1.88 and 2.04 ± 1.43, respectively). Additionally, the posttraining AJFAT scores of subjects with unstable ankles (25.78 ± 3.80) and the nonimpaired subjects (29.15 ± 5.27) were significantly greater than their pretraining scores (17.11 ± 3.44 and 22.92 ± 5.22, respectively), indicating an overall improvement in perceived ankle joint functional stability. Conclusions: This study suggests that balance training is an effective means of improving joint proprioception and single-leg standing ability in subjects with unstable and nonimpaired ankles.

J Orthop Sports Phys Ther. 1999;29(8):478-486.

Key Words: neuromuscular, proprioception, rehabilitation

Study Design: Two-factor repeated measures design. Objectives: To compare the effects of a 20-minute cold application to the effects of a 20-minute cold application followed by 20 additional minutes of intermittent cold on forearm blood flow over a 60-minute period. Background: The appropriate duration of cold application as a therapeutic modality following soft tissue trauma is an important clinical question because the goal of using this modality is to limit edema, decrease pain, and produce effective muscle relaxation without causing cold-induced reactive vasodilatation or nerve damage. Methods and Measures: Thirteen subjects (mean age, 21.46 ± 4.01 years) volunteered to participate in this study. A bilateral tetrapolar impedance plethysmograph was used with venous occlusion to measure changes in local limb blood volume at the forearm for a period of 60 minutes under 2 conditions: Condition 1: Prolonged intermittent cold application (20 minutes ice application; 10 minutes off; 10 minutes ice on; 10 minutes off; 10 minutes ice on); Condition 2: Cold followed by application of a room-temperature pack of equal weight to the ice bag (20-minute ice application; 10 minutes off; 10 minute room temperature pack on; 10 minutes off; 10-minute room-temperature pack on). Results: A significantly lower blood flow was noted during the last 10 minutes of Condition 1 compared with Condition 2. Conclusions: The findings of this study indicate that blood flow is reduced when a prolonged intermittent cold application (Condition 1) is used compared to a single cold application (Condition 2).

J Orthop Sports Phys Ther. 1999;29(3):177-180.

Key Words: cryotherapy, plethysmography, rehabilitation

There is a dearth of reliable and valid instrumentation that measures disability following injury and/or surgery of the knee joint that is responsive to clinically significant changes over time. The purpose of this investigation was to determine whether performance-based or patient-reported measures of function are more effective in estimating disability in individuals with an anterior-cruciate-ligament (ACL)-deficient knee. Subjective rating of knee function was used as the criterion measure for disability, and selected performance-based and patient-reported measures were used as estimation variables. Twenty-nine individuals with an ACL-deficient knee participated in this investigation. Step-wise regression analysis revealed that the Cincinnati Knee Scale, Lysholm Knee Scale, and hop index were the most effective estimates of disability. The results demonstrate that patient-reported measures are more related to the patient's level of disability in individuals with an ACL-deficient knee. More research is necessary to substantiate these findings.

J Orthop Sports Phys Ther. 1998;28(6):392-399.

Key Words: functional disability, anterior cruciate ligament deficiency, knee, assessment

Residual symptoms resulting from recurrent episodes of inversion-type ankle sprains may be attributed to a decreased neuromuscular response of the peroneal or tibialis anterior muscles, thereby increasing the probability for reinjury. The purpose of this study was to examine the electromyographic (EMG) response time of the peroneal and tibialis anterior muscles in response to sudden plantar flexion/inversion stress in the chronically functional unstable and normal ankle. Subjects for this study consisted of 13 athletically active individuals (5 males and 8 females, mean age = 19.2 ± 1.51 years) with a previous history of a unilateral inversion-type ankle sprain. A specially designed platform that allows each foot to drop into plantar flexion/inversion from a standing neutral position was used. Reaction time in milliseconds for the peroneal and tibialis anterior muscles to sudden plantar flexion/inversion was measured via surface EMG. A paired t test was performed with the Bonferroni-Dunn correction factor to determine differences between the peroneal and tibialis anterior as well as between the chronically unstable and contralateral normal ankle. The results indicated no significant differences between the stable and unstable ankles for the peroneal or the tibialis anterior muscles. The results also indicated no significant differences existed between the tibialis anterior and peroneal muscles in either the stable or unstable ankles. The findings from the present study suggest that self-reported functional ankle instability may not result in a diminished reflex response time of the peroneal and tibialis anterior muscles to sudden plantar flexion/inversion stress.

J Orthop Sports Phys Ther. 1997;26(2):73-77.

Key Words: electromyography, ankle, inversion, instability

Shoulder kinesthesia has not been extensively studied in upper extremity athletes. The purpose of this study was to determine if there were differences in threshold to detection of passive motion between dominant and nondominant shoulders of healthy overhead athletes in 2 positions, 0° and 75° of external rotation. In addition, the study attempted to determine if there was a relationship between the range of external rotation (ER) and internal rotation (IR) and the threshold to detection of passive motion values. Shoulder kinesthesia was assessed in the dominant and nondominant shoulders of 20 collegiate athletes participating in unilateral upper extremity sports. A proprioceptive testing device passively moved the shoulder into internal and external rotation. The dominant shoulder had a significantly greater difficulty detecting motion compared with the nondominant arm at both 0° and 75° of external rotation. Both shoulders exhibited enhanced kinesthesia (lower threshold to detection of passive motion scores) at 75° of external rotation compared with 0°, where the glenohumeral joint capsule is relatively taut. The results of this study suggest that healthy upper extremity athletes may have kinesthetic deficits in their throwing shoulder compared with their nondominant shoulder.

J Orthop Sports Phys Ther. 1995;21(4):220-262.

Key Words: shoulder, kinesthesia, athletics

Study Design: Case control group study.
Objectives: To compare scapular position and orientation between baseball players with and without pathologic internal impingement.
Background: Scapular dysfunction has been implicated as a contributor to throwing-related pathologic internal impingement of the shoulder due to its role in increasing the contact between the greater tuberosity and posterior-superior glenoid, thereby impinging the posterior rotator cuff tendon(s) and labrum. However, to date, no definitive data demonstrate this scapular dysfunction in throwing athletes. The purpose of this study was to assess, in a controlled laboratory environment, whether scapular position and orientation would be different in throwing athletes diagnosed with pathologic internal impingement than in a control group of throwing athletes.
Methods and Measures: Eleven throwing athletes diagnosed with pathologic internal impingement, using both clinical examination and a magnetic resonance arthrogram, were demographically matched with a control group of 11 throwers with no history of upper extremity injury. An electromagnetic tracking device was used to measure scapular internal/external rotation, anterior/ posterior tilt, upward/downward rotation, sternoclavicular protraction/retraction, and elevation/ depression during humeral elevation within the scapular plane. Comparisons were made between groups with analysis of variance models (P<.05).
Results: The individuals in the pathologic internal impingement group demonstrated statistically significant increased sternoclavicular elevation when elevating their humerus from 30° to 120° (P = .002) and from 60° to 120° (P = .003), compared to the control group. Furthermore, these patients also had increased posterior scapular tilt position (P = .016). No statistically significant differences were present in any other scapular variables measured.
Conclusions: Based on the results of this study, throwing athletes diagnosed with pathologic internal impingement present with statistically significant increases in sternoclavicular elevation and scapular posterior tilt position during humeral elevation in the scapular plane.

J Orthop Sports Phys Ther. 2006;36(7):485-494. doi:10.2519/jospt.2006.2146

Key Words: pathologic internal impingement, scapular kinematics, throwing athletes