STUDY DESIGN: Single cohort study. OBJECTIVES: To investigate the efficacy of real-time biofeedback provided during treadmill gait training to correct knee hyperextension in asymptomatic females while walking. BACKGROUND: Knee hyperextension is associated with increased stress to the posterior capsule of the knee joint, anterior cruciate ligament, and the anterior compartment of the tibiofemoral joint. Previous methods aimed at correcting knee hyperextension have shown limited success. METHODS: Ten women, ages 18 to 39 years, with asymptomatic knee hyperextension during ambulation, were provided with 6 sessions of real-time feedback of kinematic data (Visual 3D) during treadmill training. Gait evaluations were performed pretraining, posttraining, and 1 month after the last training session. RESULTS: Participants showed improved control of knee hyperextension during overground walking at 1.3 m/s at posttraining and at 1 month posttraining. CONCLUSION: The present study demonstrated that knee sagittal plane kinematics may be influenced by gait retraining using real-time biofeedback.

J Orthop Sports Phys Ther 2011;41(12):948-952, Epub 25 October 2011. doi:10.2519/jospt.2011.3660

KEY WORDS: gait retraining, knee alignment, knee kinematics, physical therapy

STUDY DESIGN: Clinical measurement. OBJECTIVE: To determine the validity and reliability of measures obtained using a custom-made device for assessing ankle dorsiflexion motion and stiffness. BACKGROUND: Limited dorsiflexion has been implicated in the evolution of foot pain in a number of clinical populations. Assessment of ankle dorsiflexion range of motion (ROM) is, therefore, commonly performed as part of a foot and ankle examination. Conventional goniometric assessment methods have demonstrated limited intertester reliability, while alternative methods of measurements are generally more difficult to use. The Iowa ankle range of motion (IAROM) device was designed in an attempt to develop a simple, clinically relevant, and time- and cost-effective tool to measure ankle dorsiflexion range of motion and stiffness. METHODS: Validity and intertester reliability of dorsiflexion range-of-motion measures using the IAROM device were assessed at 10, 15, 20, and 25 Nm of passively applied dorsiflexion torque, with both the knee extended and flexed approximately 20°. Stiffness (change in torque/change in dorsiflexion angle) values were determined using the angular change obtained between the 15- and 25-Nm torque levels. Convergent validity (n = 12) was assessed through comparison of ankle dorsiflexion angles measured simultaneously with the IAROM device and an optoelectronic motion analysis system. Intertester reliability (n = 17) was assessed by 2 testers who took measurements within the same day. RESULTS: Validity testing demonstrated excellent agreement (intraclass correlation coefficient [ICC] values ranging from 0.95 to 0.98). Reliability testing demonstrated good to excellent intertester agreement (ICC values ranging from 0.90 to 0.95). The ICCs for ankle joint dorsiflexion stiffness were .71 and .85 for the knee in an extended and flexed position, respectively. CONCLUSION: The IAROM device provides valid and reliable measurement of ankle dorsiflexion ROM. The IAROM device also allows calculation of stiffness by measuring ROM at multiple torque levels, although the reliability of the measurement is not optimal.

J Orthop Sports Phys Ther 2011;41(4):274-280. doi:10.2519/jospt.2011.3397

KEY WORDS: IAROM, plantar flexors, stiffness, talocrural joint

J Orthop Sports Phys Ther. 2003;33(5):273-287.

Key Words: anterior cruciate ligament, biomechanics, kinematics, knee instability

Study Design: Mixed, repeated measures design. Objectives: To determine if previous experience with loads of similar weight influences the anticipatory lifting force and postural adjustments during the squat lift. To examine a multijoint, functional task for coordination between stability and movement. To determine if lifting unexpected loads results in trunk loading patterns associated with greater risk injury. Background: Workers are increasingly exposed to variability in materials handling thereby increasing the risk of injury. Understanding the control processes underlying lifting will support clinical decision making for preparing injured workers to return to realistic working conditions. Subjects: (19 men, 4 women; mean age, 25.4 ± 3.5 y) lifted a series of boxes weighing 5%, 20%, and 35% of their maximal lifting capacity. The loads were delivered via a gravity conveyor. The identical-appearing loads were ordered so that the subjects lifted several loads of similar weight, immediately followed by a lighter or heavier than expected load based on the previous lift. Results: Generally, the vertical lifting force, force rate, horizontal momentum, and angular momentum increased with an increase in expected load. Higher peak lumbar extensor moments occurred with lighter than expected loads (expected 20% and lifted 5% load = 238.2 ± 91.2 N-m; expected 35% and lifted 5% load = 278.2 ± 101.8 N-m) compared to expected loads of similar weight (expected and lifted 5% load = 205.0 ± 73.2 N-m). Heavier than expected loads led to eccentric trunk movements when there were large mismatches between the expected and actual loads. Conclusions: The vertical lifting forces and whole body momentum were predictively scaled according to the expected load. The loading phase relationships indicated coordination between the lifting force, force rate, horizontal momentum, and angular momentum. Trunk loading during the lifts with unexpected loads showed patterns associated with increased injury risk.

J Orthop Sports Phys Ther 2OOl;3l(12):7O8-729.

Key Words: equilibrium, low back injury, posture control

Study Design: Case study. Objective: To compare knee kinematics and moments of nongiving way trials to a giving way trial during a combined stepping and crossover cutting activity. Background: The knee kinematics and moments associated with giving way episodes suggest motor control strategies that lead to instability and recovery of stability during movement. Methods and Measures: A 27-year-old woman with anterior cruciate ligament deficiency reported giving way while performing a combined stepping and crossover cutting activity. A motion analysis system recorded motion of the pelvis, femur, tibia, and foot using 3 infrared emitting diodes placed on each segment at 60 Hz. Force plate recordings at 300 Hz were combined with limb inertial properties and position data to estimate net knee joint moments. The stance time, foot progression angle, and cutting angle were also included to evaluate performance between trials. Results: Knee internal rotation during the giving way trial increased 3.2° at 54% of stance relative to the nongiving way trials. Knee flexion during the giving way trial increased to 33.1° at 66% of stance, and the knee moment switched from a nominal flexor moment to a knee extensor moment at 64% of stance. The knee abductor moment and external rotation moment during the giving way trial deviated in early stance. Conclusions: The observed response to the giving way event suggests that increasing knee flexion may enhance knee stability for this subject. The transverse and frontal plane moments appear important in contributing to the giving way event. Further research that assists clinicians in understanding how interventions can impact control of movements in these planes is necessary.

J Orthop Sports Phys Ther. 2001;31(9):481-495.

Key Words: anterior cruciate ligament deficiency, kinematics, knee kinetics

Study Design: A 3-factor (foot type, speed, and mode of ambulation) repeated-measures experimental design was used. Objectives: To compare the differences in energy expenditure, gait efficiency, and relative exercise intensity in persons with transtibial amputations with various prostheses. Background: There is a need for improved prosthetic designs to accommodate physically active persons with lower-extremity amputations. Methods and Measures: We used progressive speeds of treadmill walking (53.64, 67.05, 80.46, 93.87, and 107.28 m/min) and running (120.69, 134.1, and 147.51 m/min) with 3 different types of prostheses: the Solid Ankle Cushion Heel (SACH) foot, the Flex-Foot (FF), and the Re-Flex Vertical Shock Pylon (VSP) prosthesis. Five physically active men with unilateral transtibial amputations served as subjects (aged 31.6 ± 4.28 years). Results: The following statistically significant differences (improvements) between the Re-Flex VSP versus the FF and the SACH foot were found. Energy cost: walking (5%), running (11%); gait efficiency: walking (6%), running (9%); relative exercise intensity: walking (4%), running (5%). However, we found no significant differences between the FF and the SACH. Conclusions: The Re-Flex VSP appears to have a positive effect on energy cost, efficiency, and relative exercise intensity compared with the other prosthetic foot types during walking and running.

J Orthop Sports Phys Ther. 1999;29(9):526-533.

Key Words: energy expenditure, Flex-foot and Re-Flex VSP prostheses, gait efficiency, SACH Foot

Study Design: Case study. Objectives: To describe a protocol used in the rehabilitation of a grade II lateral ankle sprain, emphasizing brief immobilization with a removable boot, weight bearing as tolerated, and progression of early exercise. Background: The optimum conservative treatment of severe grade II ankle sprains remains undefined. Short-term benefits of early mobilization have won favor over immobilization by casting; however, pain and ankle joint instability often linger. The timing of weight bearing as a variable that influences recovery has largely been ignored when either treatment is considered. Methods and Measures: The patient was a 17-year-old girl who had sustained a left ankle inversion sprain while playing high school basketball. The sprained ankle was placed in an immobilizer boot for 1 week, and weight bearing was encouraged. She received instructions for active exercise and for resistive exercise with elastic tubing. Volumetric and active range of motion measurements and gait observation provided indicators of rehabilitation progress. A digital inclinometer was used to measure active range of motion in the sagittal plane. Vertical ground reaction forces recorded with an instrumented treadmill documented gait symmetry. Results: The patient responded well to the course of treatment, returning to full participation in basketball 2 weeks after the injury. The injured ankle had 29% (19°) less active range of motion than the nonimpaired ankle at the beginning of physical therapy. The injured ankle also displaced 50 mL more water compared with the nonimpaired ankle at the start of treatment. Four weeks after beginning treatment, the sprained ankle had 4° less active range of motion and displaced 5 mL more water compared with the nonimpaired ankle. As a college athlete, the patient has remained free of subjective complaints of ankle pain, instability, and swelling. Conclusion: Weight-bearing immobilization combined with early exercise provided safe and effective treatment for this patient, who suffered a grade II lateral ankle sprain.

J Orthop Sports Phys Ther. 1999;29(7):394-399.

Key Words: gait, immobilizer boot, rehabilitation.

Many protocols for rehabilitating the knee following anterior cruciate ligament (ACL) injury or repair call for the use of both weight-bearing and nonweight-bearing exercises. However, not much is known about the strain these exercises place on the passive restraining mechanisms. The purpose of this study was to examine the effect of progressive loading of the knee extensors on anterior tibial translation during weight-bearing and nonweight-bearing isometric exercise. Fourteen subjects diagnosed as ACL-deficient via arthroscopic surgery participated in the study. An arthrometer was used to measure anterior tibial translation during weight-bearing and nonweight-bearing exercises with the knee in 20° of flexion and with a quadriceps load equivalent to 25%, 50%, 75%, and 100% of body weight. Hamstring muscle activations during all testing were monitored to eliminate the possibility of substantial cocontractions. During the weight-bearing exercise, anterior tibial translation was found to be significantly less than that measured during the Lachman's evaluation and the 50%, 75%, and 100% nonweight-bearing exercises. For the nonweight-bearing exercises, anterior tibial translation was either equivalent to or greater than the Lachman's evaluation. During the weight-bearing exercises, anterior tibial translation was not different under the different loading conditions. During the nonweight-bearing exercises, anterior tibial translation progressively increased with increased loading. The results from this study imply that weight-bearing exercises minimize strain to the passive restraining structures whereas nonweight-bearing exercises will strain these structures, and the magnitude of this strain appears to be proportional to the knee extensor moment.

J Orthop Sports Phys Ther. 1994;20(5):247-253.

Key Words: anterior cruciate ligament, rehabilitation, biomechanics