Matthew C. Morrissey

A kinematic comparison of overground and treadmill walking

OBJECTIVE: To compare overground and treadmill ambulation for possible differences in gait temporal variables and leg joint kinematics. DESIGN: A human subject trial of walking in two conditions. BACKGROUND: The treadmill is frequently used to simulate overground ambulation; however, the literature shows a wide difference of opinion as to whether the treadmill replicates the overground environment. METHODS: A total of 17 uninjured subjects walked overground at their preferred velocity. The treadmill was then set at the average velocity obtained in overground walking. Gait temporal variables and leg joint kinematics were analysed using the three dimensional (3D) Kinemetrix Motion Analysis System. The data were analysed separately for the two gender groups and for the groups combined. RESULTS: In the females, only the maximum hip flexion angle was significantly different in the two conditions with greater flexion occurring on the treadmill. For males, significant differences were noted between the two conditions for cadence and maximum knee flexion angle with greater values in the treadmill walking. When all subjects were compared, significant increases were seen during treadmill walking in hip range of motion, maximum hip flexion joint angle and cadence, while a significant decrease was observed in stance time. CONCLUSIONS: Statistically significant differences exist between overground and treadmill walking in healthy subjects for some joint kinematic and temporal variables. RELEVANCE: The results of this and other studies demonstrate that the kinematics of human walking differ in treadmill and overground ambulation. The next step in this line of research is to assess whether the kinematic differences in the two walking conditions are exhibited in different patient groups. If differences do exist in patient groups, then the interpretation of treadmill-based gait analysis findings should not be extended to that of ground walking, particularly where the patient has an impaired hip function, such as that exemplified after total hip replacement.

Resistance training modes: specificity and effectiveness.

There is considerable demand for information on the effectiveness of various resistance exercises for improving physical performance, and on how exercise programs must match functional activities to produce the greatest performance gains (training specificity). Evidence supports exercise-type specificity; the greatest training effects occur when the same exercise type is used for both testing and training. Range-of-motion (ROM) specificity is supported; strength improvements are greatest at the exercised joint angles, with enough carryover to strengthen ROMs precluded from direct training due to injury. Velocity specificity is supported; strength gains are consistently greatest at the training velocity, with some carryover. Some studies have produced a training effect only for velocities at and below the training velocity while others have produced effects around the training velocity. The little, mainly isokinetic, evidence comparing different exercise velocities for improving functional performance suggests that faster exercise best improves fast athletic movements. Yet isometric exercise can improve actions like the vertical jump, which begin slowly. The rate of force application may be more important in training than actual movement speed. More research is needed into the specificity and efficacy of resistance exercise. Test populations should include both males and females of various ages and rehabilitation patients.

A literature review of autograft and allograft anterior cruciate ligament reconstruction

Knee anterior cruciate ligament reconstructive surgery has significantly evolved and now includes the option of using an allograft. This has resulted in numerous studies evaluating the advantages and disadvantages of allografts. The purpose of this literature review is to evaluate this research and present important findings to allow the selection of the most appropriate graft source when considering allograft versus autograft reconstruction.

The effects of electrical stimulation on the quadriceps during postoperative knee immobilization

Immobilization of the knee after anterior cruciate liga ment (ACL) reconstructon results in marked thigh atro phy and decrease in quadriceps strength that may prolong the rehabilitation program of the injured athlete. Fifteen male volunteers undergoing ACL reconstruction were divided into two groups, stimulation (during im mobilization) and nonstimulation. Measurements of thigh circumference and isometric quadriceps strength were tested preoperatively, immediately after cessation of cast immobilization (6 weeks), and at 9 and 12 weeks postoperatively. The changes in circumference and strength between the first preoperative test and all subsequent tests were compared for statistical signifi cance (Students t-test, P < 0.5) between the two groups. The decrease in quadriceps strength of the stimulation group during immobilization was signifi cantly less than that of the nonstimulation group, al though later differences between the two groups were not significant. There were no significant differences in thigh atrophy between the two groups. In conclusion, isometric quadriceps torque decreases resulting from immobilization can be significantly lessened by appli cation of electrical stimulation during immobilization. Electrical stimulation to the quadriceps does not sig nificantly alter thigh circumference changes that occur during immobilization.

Increases in muscle volume after plantarflexor strength training in children with spastic cerebral palsy

Children with spastic cerebral palsy (CP) have small, weak muscles. However, change in muscle size due to resistance training in this group is unknown. We investigated the effect of plantarflexor strengthening on muscle volume, gait, and function in 13 ambulant children with spastic CP (seven males, six females; mean age 10y 11mo, SD 3y 0mo, range 6y 11mo–16y 11mo; eight with diplegia, five with hemiplegia; Gross Motor Function Classification System level I, six; level II, five; level III, two). Assessments were performed before training, 5 and 10 weeks into training, and at a 3‐month follow‐up. Medial and lateral gastrocnemius volumes were computed from three‐dimensional ultrasound images. The number of unilateral heel raises able to be achieved on each side was assessed. Function was measured using three‐dimensional gait analysis, the ‘timed up and go’ test, the Gillette Functional Assessment Questionnaire, and the Functional Mobility Scale. Training involved heel raises or Thera‐Band resistance, 4 times a week for 10 weeks. Medial and lateral gastrocnemius volumes increased by 17 and 14% at week 5 (p=0.03, p=0.028). This increase was maintained at week 10 and follow‐up (medial gastrocnemius p=0.001, p<0.001; lateral gastrocnemius p=0.006, p=0.007). Heel raises (mean number) increased by week 5 (p=0.002). This was maintained at week 10 and follow‐up (p<0.001; p<0.001). No significant change in measured function was observed. Muscle volume increased in response to training in children with spastic CP. The role of progressive strength training in maintaining long‐term function is discussed.

Effects of open versus closed kinetic chain training on knee laxity in the early period after anterior cruciate ligament reconstruction

Abstract. Knee extensor resistance training using open kinetic chain (OKC) exercise for patients recovering from anterior cruciate ligament reconstruction (ACLR) surgery has lost favour mainly because of research indicating that OKC exercise causes greater ACL strain than closed kinetic chain (CKC) exercise. In this prospective, randomized clinical trial the effects of these two regimes on knee laxity were compared in the early period after ACLR surgery. Thirty-six patients recovering from ACLR surgery (29 males, 7 females; age mean=30) were tested at 2 and 6 weeks after ACLR with knee laxity measured using the Knee Signature System arthrometer. Between tests subjects trained using either OKC or CKC resistance of their knee and hip extensors in formal physical therapy sessions three times per week. Following adjustment for site of treatment, pretraining injured knee laxity, and untreated knee laxity at post-training, the use of OKC exercise, when compared to CKC exercise, was found to lead to a 9% increase in looseness with a 95% confidence interval of –8% to +29%. These results indicate that the great concern about the safety of OKC knee extensor training in the early period after ACLR surgery may not be well founded.

Open and Closed Kinetic Chain Exercises in the Early Period after Anterior Cruciate Ligament Reconstruction: Improvements in Level Walking, Stair Ascent, and Stair Descent

Thirty-seven patients who had undergone anterior cruciate ligament reconstruction were tested in a gait analysis laboratory at 2 and 6 weeks after surgery. Between test sessions, patients were randomly assigned to a course of either closed or open kinetic chain resistance exercises (3 sessions per week for 4 weeks). Gait analysis consisted of bilateral calculations of knee joint angle, moment, and power during level walking, stair ascent, and stair descent. An analysis of variance on the effects of training group and test session indicated that the only variable to be significantly affected by the type of exercise program was the amount of knee flexion at the beginning of step-up (P<0.05). All other measures of knee angle, moment, and power (16 total variables) showed no significant difference between the exercise groups. All variables measured on the injured side showed significant improvement from test 1 to test 2 (P<0.05), but the injured leg remained functionally deficient when compared with the uninjured leg. These data suggest that there are no clinically significant differences in the functional improvement resulting from the choice of open or closed kinetic chain exercises in the early period after this surgery.

Static pre-load effect on knee extensor isokinetic concentric and eccentric performance

The effect of two static pre-load levels on isokinetic concentric (CON) and eccentric (ECC) performance of the knee extensors at 90 degrees.s-1 was evaluated in 35 healthy subjects. The low pre-load level was 50 N, and the high level was 75% of a maximal voluntary isometric contraction, performed at the start angles of 100 degrees (CON) and 30 degrees (ECC) of knee flexion. A two-way ANOVA with two repeated measures (load and angle) and a Newman-Keuls post hoc analysis were performed to compare the interaction of pre-load and angle at every 5 degrees in the ROM. The differences in average torque, peak torque, and peak torque angle between the pre-load levels were also analyzed with repeated-measures t-tests. The high pre-load condition had a significant increase in torque at 99, 95, 90, and 85 degrees concentrically and 31, 35, 40, 45, and 50 degrees eccentrically. In comparing the two pre-load conditions over the whole torque curve, there was a significant difference in average torque values of both CON and ECC, no significant difference in peak torque in either contraction, and a significant shift in peak torque angle with CON contractions only.

Effect of neuromuscular electrical stimulation on foot/ankle volume during standing

PURPOSE The purpose of this study was to assess whether the increase in foot and ankle volume after 30 min of motionless standing in healthy subjects could be minimized by neuromuscular electrical stimulation (NMES). METHODS A crossover, counterbalanced design was used where foot and ankle volume in 20 healthy subjects was measured using water volumetry before and after 30 min of motionless standing and standing with NMES applied to the lower leg muscles. The NMES produced repeated tetanic contractions of the gastrocnemius and tibialis anterior muscles causing slight ankle dorsi- and plantar-flexion. RESULTS Posttest foot and ankle volume was significantly greater than pretest volume after 30 min of motionless standing (t = -7.093, P < 0.001), but no significant differences were found after 30 min of standing with NMES (t = -1.374, P = 0.185). The mean volume changes from pretest to posttest in the conditions without NMES and with NMES were significantly different (51 +/- 32 mL and 12 +/- 39 mL, respectively; t = 3.905, P = 0.001). CONCLUSION This study demonstrates the potential uses of NMES as a means to reduce swelling in the lower limbs for individuals who do not fully activate the musculo-venous pump. The activation of the musculo-venous pump by NMES-induced muscle contraction may have minimized the increase in foot and ankle volume by increasing venous return, reducing venous stasis, increasing lymph flow, and increasing interstitial hydrostatic pressure, which would reduce capillary filtration and assist fluid reabsorption.

Gait analysis 6 and 12 months after anterior cruciate ligament reconstruction surgery.

Little is known about knee function after anterior cruciate ligament reconstruction in the vital activities of walking and stair use. Gait analysis was done on patients 6 months (n = 8) and 12 months (n = 9) after reconstruction of the anterior cruciate ligament. Paired t tests were used to compare the injured and uninjured knees. During level walking, the patients placed external flexion torques on their injured knees throughout midstance, indicating the absence of quadriceps avoidance gait. The peak external flexion torque (resisted by the knee extensor muscles) placed on the injured knee was significantly less than that of the uninjured knee when ascending stairs (at 12 months, 68.4 and 85.3 N-m in the injured and uninjured knees, respectively) and also when descending stairs (at 12 months, 70.8 and 81.7 N-m in the injured and uninjured knees, respectively). The injured knee produced significantly less power than the uninjured knee when ascending stairs, but this difference was not significant when descending stairs. These findings indicate that asymmetric gait patterns persisted up to 1 year after surgical reconstruction and were more pronounced during stair ascent and descent than in level walking. These results indicate that clinicians should include specific interventions targeted at improving knee function during stair use to restore normal function after anterior cruciate ligament reconstruction.