The effect of two types of foot orthoses on rearfoot mechanics.

Little experimental data exist regarding the comparative biomechanical of various foot orthoses. This study evaluated the comparative effect of biomechanical orthoses and over-the-counter arch supports on controlling rearfoot pronation. Twenty-four patients with forefoot varus deformity were studied while walking on a treadmill. Two-dimensional, videotape motion analysis was used for studying rearfoot mechanics with three experimental conditions: 1) shoes only, 2) shoes plus arch supports, and 3) shoes plus biomechanical orthoses. The variables studied were: maximum pronation, calcaneal eversion, maximum pronation velocity, time-to-maximum pronation, and total pronation. No difference was noted in maximum pronation, calcaneal eversion, and total pronation between the three conditions. The data for maximum pronation velocity and time-to-maximum pronation were not reliable. Based on the results of this study, padded arch supports nor biomechanical orthoses can be preferentially recommended for their ability to control maximum pronation, calcaneal eversion, and total pronation during walking. Additional research is necessary to: 1) identify the biomechanical effects that are responsible for the clinical success of foot orthoses, and 2) determine better designs for controlling rearfoot movement.

Effects of three different posting methods on controlling abnormal subtalar pronation.

BACKGROUND AND PURPOSE: The purpose of this study was to determine the effects of different orthotic posting methods on controlling abnormal foot pronation during ambulation. SUBJECTS: Twenty-two individuals with forefoot varus deformities of at least 8 degrees (13 women, aged 21-40 years, and 9 men, aged 20-50 years) participated in the study. The female subjects had an average height and weight of 162.6 cm (64 in) and 55.3 kg (122 lb), and the male subjects had an average height and weight of 175.3 cm (69 in) and 80.7 kg (178 lb). METHODS: The subjects were examined with a computerized video motion analysis system. A control trial consisted of walking at 4.0 km/h in running shoes. Experimental trials included walking at 4.0 km/h in running shoes with unposted orthotic shells and with orthotic shells posted in the forefoot, the rear foot, and both forefoot and rear foot. RESULTS: Maximal calf-to-calcaneus and calcaneus-to-vertical angles were decreased more by orthoses posted in both the forefoot and the rear foot than by orthoses posted only in the forefoot. No difference in maximal calf-to-calcaneus and calcaneus-to-vertical angles were found with combined forefoot and rear-foot posting compared with posting in the rear foot alone. The maximal calf-to-calcaneus angle was decreased by orthoses posted in any of the three methods and by the orthotic shell alone when compared with shoes alone. The maximal calcaneus-to-vertical angle was decreased by orthoses posted in any of the three methods, but not by the orthotic shell alone when compared with shoes alone. CONCLUSION AND DISCUSSION: Clinicians should consider combined posting or rear-foot posting alone when maximal control of rear-foot frontal-plane pronation is desired, though forefoot posting alone and the orthotic shell also provide control of rear-foot frontal-plane pronation.

Effects of strength training on throwing velocity and shoulder muscle performance in teenage baseball players.

Exercise protocols designed to improve muscle function and athletic performance are continually developed and revised, often without published research supporting their efficacy. This study compared the effects of isokinetic (IKN) and accommodative isotonic training in the individualized, dynamic, variable resistance (IDVR) mode. Twenty-seven teenage baseball players were tested isokinetically for dominant shoulder rotational peak torque and power and for throwing velocity. They were then randomly assigned to 5 weeks of IKN training, IDVR training, or a control group of no training. Following the training period, pretest protocols were repeated. Analysis of variance of differences in means and Newman-Keuls post hoc tests showed statistically significant increases in throwing velocity and external rotator torque in the IDVR group but not the IKN group. External rotator power improved in both groups. Internal rotator torque and power were not improved in either group. Results suggest that IDVR may be more effective than IKN training in improving throwing velocity and external rotator torque production. Clinicians should consider using IDVR protocols in improving shoulder muscle function and throwing performance. J Orthop Sports Phys Ther 1992;15(5):223-228.

Isokinetic evaluation of shoulder rotational strength between the plane of scapula and the frontal plane.

The purpose of this study was to determine whether shoulder rotational strength was greater in the plane of the scapula or the frontal plane. Isokinetic shoulder rotational strength was evaluated in 20 subjects. Using the Merac (Universal Gym Equipment, Inc., Cedar Rapids, IA), test data was gathered in the right shoulders, in 45 degrees abduction, at a speed of 60 deg/sec, in the plane of the scapula and the frontal plane. Each subject returned within 1 week for retests to establish reliability. The average correlational coefficient across tests was 0.87. The Merac computer system was used to analyze data. Mean and standard deviations for peak torque to body weight were calculated. A paired t-test was used to examine the difference in the means for internal and external rotation between the two positions. The results indicated no significant difference between the two positions for shoulder internal rotational strength values. However, shoulder external rotational strength values in the plane of the scapula were statistically significantly higher than in the frontal plane (P less than 0.001). These preliminary results suggest isokinetic strength training and testing may be preferable in the plane of the scapula rather than the frontal plane.

Preseason screening of the lumbar spine.

The author proposes a step-by-step method of lumbar spine examination which can be incorporated into the large scale preseason athletic participation screening process. This paper lists and describes examination techniques which can be administered quickly and accurately to large numbers of athletes in succession. In addition, the paper delineates two levels of proficiency required to perform the examination, outlines a practical format, and discusses general and specific precautions and contraindications to participation. J Orthop Sports Phys Ther 1981;3(1):6-10.