Predictive validity of an injury score among high school basketball players.

A number of strategies have been investigated in an attempt to identify those individuals most likely to be injured during participation in sports activity. One such strategy identified in the literature involved computing an "injury score" via a logistic regression equation using measures of structural symmetry to predict the likelihood of athletic injury. The purpose of this study was to investigate the predictive value of the injury score among high school basketball players. Following the establishment of reliability of measures, injury scores were calculated for 62 high school basketball players (34 females, 28 males) before the start of the season. Lower extremity injuries sustained while playing basketball were recorded throughout the season. The predictive value of the injury score equation was determined by calculating sensitivity, specificity, and positive and negative predictive values. The sensitivity and specificity were calculated to be 16.7% and 66.1%, respectively. The positive and negative predictive values were calculated to be 5.90% and 88.1%, respectively. These results indicate that the injury prediction score investigated was not a valid means of predicting injury in high school basketball players. Limitations, possible implications of these findings, and ideas for future related research are presented.

The effect of time on static stretch on the flexibility of the hamstring muscles.

BACKGROUND AND PURPOSE: To date, there are no reports comparing duration of static stretch in humans on joint range of motion (ROM) and hamstring muscle flexibility. The purpose of this study was to examine the length of time the hamstring muscles should be placed in a sustained stretched position to maximally increase ROM. SUBJECTS: Fifty-seven subjects (40 men, 17 women), ranging in age from 21 to 37 years and with limited hamstring muscle flexibility (ie, 30 degrees loss of knee extension measured with femur held at 90 degrees of hip flexion), were randomly assigned to one of four groups. Three groups stretched 5 days per week for 15, 30, and 60 seconds, respectively. The fourth group, which served as a control group, did not stretch. METHODS: Before and after 6 weeks of stretching, flexibility of the hamstring muscles was determined by measuring knee extension ROM with the femur maintained in 90 degrees of hip flexion. Data were analyzed with a 4 x 2 analysis of variance (group x test) for repeated measures on one variable. RESULTS: The data analysis revealed a significant group x test interaction, indicating that the change in flexibility was dependent on the duration of stretching. Further post hoc analysis revealed that 30 and 60 seconds of stretching were more effective at increasing flexibility of the hamstring muscles (as determined by increased ROM of knee extension) than stretching for 15 seconds or no stretching. In addition, no significant difference existed between stretching for 30 seconds and for 1 minute, indicating that 30 seconds of stretching the hamstring muscles was as effective as the longer duration of 1 minute. CONCLUSION AND DISCUSSION: The results of this study suggest that a duration of 30 seconds is an effective time of stretching for enhancing the flexibility of the hamstring muscles. Given the information that no increase in flexibility of the hamstring muscles occurred by increasing the duration of stretching from 30 to 60 seconds, the use of the longer duration of stretching for an acute effect must be questioned.

Changes in torque and electromyographic activity of the quadriceps femoris muscles following isometric training.

BACKGROUND AND PURPOSE: The purpose of this study was to examine the effect of isometric training of the quadriceps femoris muscles, at different joint angles, on torque production and electromyographic (EMG) activity. SUBJECTS: One hundred seven women were randomly assigned to one of four groups. Three groups trained with isometric contractions three times per week at a knee flexion angle of 30, 60, or 90 degrees. The fourth group, which served as a control, did not exercise. METHODS: Isometric torque was measured using a dynamometer, and EMG activity was measured using a multichannel EMG system. Measurements were obtained during maximal isometric contraction of the quadriceps femoris muscles at 15-degree increments from 15 to 105 degrees of knee flexion. Measurements were taken before and after 8 weeks of training. RESULTS: Following isometric exercise, increased torque and EMG activity occurred not only at the angle at which subjects exercised, but also at angles in the range of motion at which exercise did occur. Further analyses indicated that exercising in the lengthened position for the quadriceps femoris muscles (90 degrees of knee flexion) produced increased torque across all angles measured and appeared to be the more effective position for transferring strength and EMG activity to adjacent angles following isometric training as compared with the shorter positions of the muscle (30 degrees and 60 degrees of knee flexion). CONCLUSION AND DISCUSSION: These findings suggest that an efficient method for increasing isometric knee extension torque and EMG activity throughout the entire range of motion is to exercise with the quadriceps femoris muscles in the lengthened position.

The effect of time and frequency of static stretching on flexibility of the hamstring muscles.

BACKGROUND AND PURPOSE: Frequency and duration of static stretching have not been extensively examined. Additionally, the effect of multiple stretches per day has not been evaluated. The purpose of this study was to determine the optimal time and frequency of static stretching to increase flexibility of the hamstring muscles, as measured by knee extension range of motion (ROM). SUBJECTS: Ninety-three subjects (61 men, 32 women) ranging in age from 21 to 39 years and who had limited hamstring muscle flexibility were randomly assigned to one of five groups. The four stretching groups stretched 5 days per week for 6 weeks. The fifth group, which served as a control, did not stretch. METHODS: Data were analyzed with a 5 x 2 (group x test) two-way analysis of variance for repeated measures on one variable (test). RESULTS: The change in flexibility appeared to be dependent on the duration and frequency of stretching. Further statistical analysis of the data indicated that the groups that stretched had more ROM than did the control group, but no differences were found among the stretching groups. CONCLUSION AND DISCUSSION: The results of this study suggest that a 30-second duration is an effective amount of time to sustain a hamstring muscle stretch in order to increase ROM. No increase in flexibility occurred when the duration of stretching was increased from 30 to 60 seconds or when the frequency of stretching was increased from one to three times per day.

Relationship between Peak Torque, Work, and Power for Knee Flexion and Extension in Clients with Grade I Medial Compartment Sprains of the Knee.

Past research has reported a high level of correlation between peak torque (PT) and work and between PT and power in the muscles surrounding normal and selected pathological knees. No research to date has examined whether such similarities exist in clients with pathology to the medial compartment of the knee. The purpose of this study was to investigate the relationship between the isokinetic parameters of PT, work, and power for the flexor and extensor muscle groups of patients with grade I medial compartment knee sprains. Isokinetic data were collected from 77 patients (41 males, 36 females; mean age 24.6 yrs) on a Merac dynamometer at the speeds of 60, 180, 300, and 420 degrees /set. The ranges of Pearson correlations between PT and work and between PT and power were 0.75-0.96 for the involved knee flexors, 0.67-0.99 for the involved knee extensors, 0.76-0.98 for the uninvolved knee flexors, and 0.85-0.97 for the uninvolved knee extensor muscles. These findings suggest that PT is representative of work and power and may be the only necessary parameter for isokinetic muscle performance testing of the flexor and extensor muscles of the knee in clients with grade I medial compartment sprain. J Orthop Sports Phys Ther 1992;16(6):288-292.

Kinematic effects of heel lift use to correct lower limb length differences*.

The effect of the heel lift to correct a limb length difference was studied by electrogoniometry (elgons) in four male subjects with a limb length inequality between 3/~6 inch (0.48 cm) and 3h inch (0.95 cm). Six elgons were attached to bilateral hip, knee, and ankle joints as the subject walked (3 mph) and jogged (6 mph) on the treadmill twice, once with the heel lift and once without. Recordings from the elgons examined maximal flexion and extension during support and swing phase, amplitude of movement (ROM), duration of each movement, and angular velocity of each joint. Within the limitations of the study, the following conclusions were drawn: 1) the addition of a heel lift did not appear to significantly affect biomechanical measures of gait; and 2) insertion of a heel lift did tend to cause more symmetrical movement for the maximum angle of hip extension and ROM of the swing plantarflexion phase of the ankle but more asymmetrical ROM of the swing flexion phase of the knee. J Orthop Sports Phys Ther 1986;7(4):173-179.

Case study: compression fracture of thoracic spine with emphasis on fabrication of a protective pad for athletic participation.

Preparation for return to full competition by an injured athlete can be enhanced by the use of a protective pad. This article presents the fabrication of a protective pad for a compression fracture of TI, with resulting prominence of the spinous process. The mechanism of injury of a compression fracture for the thoracic vertebrae is discussed and general guidelines for the proper construction of a pad are presented. J Orthop Sports Phys Ther 1982;4(2):115-117.

Intramachine and intermachine reliability for selected dynamic muscle performance tests.

The Cybex 6000 isokinetic dynamometer is a new isokinetic device for which no published reports of reliability have been presented in the literature. In addition, the manufacturer not only claims that the new Cybex 6000 is reliable but that torque data obtained from the Cybex 6000 are consistent with data obtained from past Cybex systems, such as the Cybex II. The purpose of this study was to investigate the intramachine reliability of the Cybex 6000 to itself and the intermachine reliability of the Cybex 6000 and the Cybex II. Data on peak torque, work, and power were collected using the Cybex 6000, and data on peak torque were obtained using the Cybex II for knee flexion and extension in 20 volunteers (10 males, 10 females). Subjects were tested three times, twice on the Cybex 6000 and once on the Cybex II, approximately 1 week apart across a 3-week period of time at angular velocities of 60, 180, and 300 degrees/sec. Data were analyzed using intraclass correlations. Results indicated that the majority of test-retest correlation coefficients for all parameters for intramachine reliability of the Cybex 6000 were above .90. Comparing peak torque obtained with the Cybex 6000 to that obtained with the Cybex II (intermachine reliability), correlation coefficients ranged from .72 to .89. In conclusion, information obtained on the Cybex 6000 appears to be quite reliable in a test-retest situation using the same equipment and moderately reliable when compared to the Cybex II. Clinical implications for these results are discussed.

The effect of static stretch and dynamic range of motion training on the flexibility of the hamstring muscles.

To date, limited information exists describing a relatively new stretching technique, dynamic range of motion (DROM). The purpose of this study was to compare the effects of DROM with static stretch on hamstring flexibility. Fifty-eight subjects, ranging in age from 21 to 41 years and with limited hamstring flexibility (defined as 30 degrees loss of knee extension measured with the femur held at 90 degrees of hip flexion), were randomly assigned to one of three groups. One group performed DROM 5 days a week by lying supine with the hip held in 90 degrees of flexion. The subject then actively moved the leg into knee extension (5 seconds), held the leg in end range knee extension for 5 seconds, and then slowly lowered the leg to the initial position (5 seconds). These movements were performed six times per session (30 seconds of total actual stretching time). The second group performed one 30-second static stretch, 5 days per week. The third group served as a control group and did not stretch. Before and after 6 weeks of training, flexibility of the hamstring muscles was determined in all three groups by measuring knee extension range of motion (ROM) with the femur maintained in 90 degrees of hip flexion. Data were analyzed with a 2 x 3 (test x group) two-way analysis of variance (ANOVA) with repeated measures on one variable (test) and appropriate post hoc analyses. The results of the two-way ANOVA revealed a significant interaction. Further statistical post hoc analysis of data to interpret the interaction revealed significant differences between the control group (gain = 0.70 degree) and both stretching groups, as well as a significant difference between the static stretch group (gain = 11.42 degrees) and the DROM group (gain = 4.26 degrees). The results of this study suggest that, although both static stretch and DROM will increase hamstring flexibility, a 30-second static stretch was more effective than the newer technique, DROM, for enhancing flexibility. Given the fact that a 30-second static stretch increased ROM more than two times that of DROM, the use of DROM to increase flexibility of muscle must be questioned.

An introduction to the plica.

Physical therapy literature has been void of information concerning the plica. The authors discuss the literature available past and present. Using current published information and clinical experience, the authors have described the functional anatomy, the evaluation, the surgery, and the prevention and postoperative rehabilitation programs. Case studies were used to demonstrate conservative and nonconservative approaches in treating the plica syndrome. J Orthop Sports Phys Ther 1982;3(4):171-177.

Rehabilitation of the ruptured biceps brachii muscle of an athlete.

The purposes of this case study are to report on the successful rehabilitation program of a college football player diagnosed as having a ruptured biceps brachii muscle and to discuss the basic rehabilitation concepts used for treatment planning. A review of the literature indicated agreement that the ruptured biceps brachii is a rare event, but the pathology does occur, and the opportunity for the clinician to evaluate and treat the injury may arise. Following a rupture of the biceps brachii muscle, a player was treated conservatively (nonsurgically) using rehabilitation concepts that included ice during acute phase; heat during chronic phase; submaximal exercise prior to maximal exercise; multiple angle isometric exercise prior to isotonic and isokinetic exercise; and functional progression to field activities. The athlete was able to avoid surgery, successfully return to competition in three weeks, and compete in the final five football games without reinjury. One year follow-up evaluation revealed that the athlete had full strength with no residual problems, a finding not commonly reported in conservatively treated biceps brachii ruptures. J Orthop Sports Phys Ther 1991;13(4):184-190.

Relationship of isokinetic peak torque with work and power for ankle plantar flexion and dorsiflexion.

Past research has analyzed the relationship of peak torque with work and power on the muscles surrounding the knee with correlation coefficients being reported, ranging from .67 to .99. No studies to date have examined this relationship for muscles surrounding the ankle joint. The purpose of this study was to analyze the relationship of peak torque with work and power for the plantar flexor and dorsiflexor muscles of the ankle. Isokinetic data were collected from 15 healthy subjects (six males, nine females; mean age = 26.6 years) on an isokinetic dynamometer across two trials at speeds of 30 and 120 degrees/sec. The results of Pearson product moment correlations between peak torque to work and peak torque to power indicated correlation coefficients ranging from .81 to .97 for all speeds of testing and angular velocities. These findings suggest that peak torque is representative of work and power.

Adaptation of skeletal muscle to resistance training.

This paper was prepared in partial fulfillment for Doctoral Degree in Physical Therapy at Texas Woman's University in Houston, TX. Resistance training is frequently used in rehabilitation to improve musculoskeletal function. The increased ability of skeletal muscle to generate force following resistance training results from two important changes: 1) the adaptation of the muscle fiber, and 2) the extent to which the motor unit can activate the muscle (neural adaption). The purpose of this article is to provide a review of research investigating the effects of resistance training on muscle fibers and on nervous system input. Muscle fiber adaptations caused by resistance training include increased cross-sectional area of the muscle (hypertrophy, hyperplasia, or both), selective hypertrophy of fast twitch fibers, decreased or maintained mitochondrial number and capillary density of muscle, and possible changes in energy sources. Changes in nervous system input resulting from resistance training include recruitment of an increased number and firing rate of motor units, increased reflex potentiation, and improved synchronization. An understanding of the adaptations occurring in muscle in response to resistance training provides a fundamental basis for which appropriate clinical exercise training programs can be developed for the rehabilitation of patients. J Orthop Sports Phys Ther 1990;12(6):248-255.

False aneurysm--a complication following an inversion ankle sprain: a case report.

Sprains of the lateral ligamentous structures of the ankle joint as a result of inversion are common and frequently result in pain. In most cases, the pain is related to soft-tissue injury and the associated hemorrhage and swelling. This case report describes the complication of posttraumatic false aneurysm of the peroneal artery following an inversion ankle sprain in a 22-year-old athlete, a complication which should be added to the differential diagnosis as a rare, but important possibility. Emphasis of the case report is placed on the rehabilitation of the patient following medical intervention.

A case study: the importance of a dynamic evaluation in the assessment of posterior knee pain.

To evaluate and treat knee problems, it is important to have an understanding of the functional anatomy of the structures about the knee joint. Injuries involving the musculature that insert or originate about the knee can cause pain leading to loss of function. The gastrocnemius muscle, primarily a plantarftexor of the ankle; is also a flexor of the knee joint due to its origin just above the lateral and medial femoral condyles on the posterior surface of the femur.' The following case report is of a strain to the medial head of the gastrocnemius which resulted in pain located at the posteriormedial region of the knee. A differential test to distinguish between a lesion of the gastrocnemius and the posterior capsule of the knee is presented.J Orthop Sports Phys Ther 1983;5(3):132-133.

Injury Profile of Northeastern Ohio High School Basketball Officials.

In brief: Little is known about the nature, location, and mechanism of injuries among basketball officials. The purpose of the present study was to develop an injury profile for this group. A total of 145 high school basketball officials were surveyed by means of a questionnaire. Sixty-one officials (42.1%) reported 71 injuries, 59 of which (83.1%) occurred in the lower extremity. Most injuries were related to change of direction or speed while running, a contrast to football, in which more injuries to officials are from collisions with players. Overall, basketball officials seem to have a lower injury rate than football officials.