Manual therapy directed at the knee or lumbopelvic region does not influence quadriceps spinal reflex excitability.

UNLABELLED: Manual therapies, directed to the knee and lumbopelvic region, have demonstrated the ability to improve neuromuscular quadriceps function in individuals with knee pathology. It remains unknown if manual therapies may alter impaired spinal reflex excitability, thus identifying a potential mechanism in which manual therapy may improve neuromuscular function following knee injury. AIM: To determine the effect of local and distant mobilisation/manipulation interventions on quadriceps spinal reflex excitability. METHODS: Seventy-five individuals with a history of knee joint injury and current quadriceps inhibition volunteered for this study. Participants were randomised to one of five intervention groups: lumbopelvic manipulation (grade V), lumbopelvic manipulation positioning (no thrust), grade IV patellar mobilisation, grade I patellar mobilisation, and control (no treatment). Changes in spinal reflex excitability were quantified by assessing the Hoffmann reflex (H-reflex), presynaptic, and postsynaptic excitability. A hierarchical linear-mixed model for repeated measures was performed to compare changes in outcome variables between groups over time (pre, post 0, 30, 60, 90 min). RESULTS: There were no significant differences in H-reflex, presynaptic, or postsynaptic excitability between groups across time. CONCLUSIONS: Manual therapies directed to the knee or lumbopelvic region did not acutely change quadriceps spinal reflex excitability. Although manual therapies may improve impairments and functional outcomes the underlying mechanism does not appear to be related to changes in spinal reflex excitability.

Different exercise training interventions and drop-landing biomechanics in high school female athletes.

CONTEXT: Anterior cruciate ligament (ACL) injuries are common in female athletes and are related to poor neuromuscular control. Comprehensive neuromuscular training has been shown to improve biomechanics; however, we do not know which component of neuromuscular training is most responsible for the changes. OBJECTIVE: To assess the efficacy of either a 4-week core stability program or plyometric program in altering lower extremity and trunk biomechanics during a drop vertical jump (DVJ). DESIGN: Cohort study. SETTING: High school athletic fields and motion analysis laboratory. PATIENTS OR OTHER PARTICIPANTS: Twenty-three high school female athletes (age = 14.8 ± 0.8 years, height = 1.7 ± 0.07 m, mass = 57.7 ± 8.5 kg). INTERVENTION(S): Independent variables were group (core stability, plyometric, control) and time (pretest, posttest). Participants performed 5 DVJs at pretest and posttest. Intervention participants engaged in a 4-week core stability or plyometric program. MAIN OUTCOME MEASURE(S): Dependent variables were 3-dimensional hip, knee, and trunk kinetics and kinematics during the landing phase of a DVJ. We calculated the group means and associated 95% confidence intervals for the first 25% of landing. Cohen d effect sizes with 95% confidence intervals were calculated for all differences. RESULTS: We found within-group differences for lower extremity biomechanics for both intervention groups (P ≤ .05). The plyometric group decreased the knee-flexion and knee internal-rotation angles and the knee-flexion and knee-abduction moments. The core stability group decreased the knee-flexion and knee internal-rotation angles and the hip-flexion and hip internal-rotation moments. The control group decreased the knee external-rotation moment. All kinetic changes had a strong effect size (Cohen d > 0.80). CONCLUSIONS: Both programs resulted in biomechanical changes, suggesting that both types of exercises are warranted for ACL injury prevention and should be implemented by trained professionals.

Baseline-dependent effect of noise-enhanced insoles on gait variability in healthy elderly walkers.

The purpose of this study was to determine whether providing subsensory stochastic-resonance mechanical vibration to the foot soles of elderly walkers could decrease gait variability. In a randomized double-blind controlled trial, 29 subjects engaged in treadmill walking while wearing sandals customized with three actuators capable of producing stochastic-resonance mechanical vibration embedded in each sole. For each subject, we determined a subsensory level of vibration stimulation. After a 5-min acclimation period of walking with the footwear, subjects were asked to walk on the treadmill for six trials, each 30s long. Trials were pair-wise random: in three trials, actuators provided subsensory vibration; in the other trials, they did not. Subjects wore reflective markers to track body motion. Stochastic-resonance mechanical stimulation exhibited baseline-dependent effects on spatial stride-to-stride variability in gait, slightly increasing variability in subjects with least baseline variability and providing greater reductions in variability for subjects with greater baseline variability (p<.001). Thus, applying stochastic-resonance mechanical vibrations on the plantar surface of the foot reduces gait variability for subjects with more variable gait. Stochastic-resonance mechanical vibrations may provide an effective intervention for preventing falls in healthy elderly walkers.

Lumbopelvic joint manipulation and quadriceps activation of people with patellofemoral pain syndrome.

CONTEXT: Quadriceps weakness and inhibition are impairments associated with patellofemoral pain syndrome (PFPS). Lumbopelvic joint manipulation has been shown to improve quadriceps force output and inhibition, but the duration of the effect is unknown. OBJECTIVE: To determine whether quadriceps strength and activation are increased and maintained for 1 hour after high-grade or low-grade joint mobilization or manipulation applied at the lumbopelvic region in people with PFPS. DESIGN: Randomized controlled clinical trial. SETTING: University laboratory. PATIENTS OR OTHER PARTICIPANTS: Forty-eight people with PFPS (age = 24.6 ± 8.9 years, height = 174.3 ± 11.2 cm, mass = 78.4 ± 16.8 kg) participated. INTERVENTION(S): Participants were randomized to 1 of 3 groups: lumbopelvic joint manipulation (grade V), side-lying lumbar midrange flexion and extension passive range of motion (grade II) for 1 minute, or prone extension on the elbows for 3 minutes. MAIN OUTCOME MEASURE(S): Quadriceps force and activation were measured using the burst superimposition technique during a seated isometric knee extension task. A 2-way repeated-measures analysis of variance was performed to compare changes in quadriceps force and activation among groups over time (before intervention and at 0, 20, 40, and 60 minutes after intervention). RESULTS: We found no differences in quadriceps force output (F(5.33,101.18) = 0.65, P = .67) or central activation ratio (F(4.84,92.03) = 0.38, P = .86) values among groups after intervention. When groups were pooled, we found differences across time for quadriceps force (F(2.66,101.18) = 5.03, P = .004) and activation (F(2.42,92.03) = 3.85, P = .02). Quadriceps force was not different at 0 minutes after intervention (t(40) = 1.68, P = .10), but it decreased at 20 (t(40) = 2.16, P = .04), 40 (t(40) = 2.87, P = .01) and 60 (t(40) = 3.04, P = .004) minutes after intervention. All groups demonstrated decreased quadriceps activation at 0 minutes after intervention (t(40) = 4.17, P < .001), but subsequent measures were not different from preintervention levels (t(40) range, 1.53-1.83, P > .09). CONCLUSIONS: Interventions directed at the lumbopelvic region did not have immediate effects on quadriceps force output or activation. Muscle fatigue might have contributed to decreased force output and activation over 1 hour of testing.

Effect of a supervised hip flexor stretching program on gait in elderly individuals.

OBJECTIVE: To determine whether a 10-week supervised hip flexor stretching program in healthy elderly subjects would increase peak hip extension, stride length and gait speed and reduce anterior pelvic tilt during walking. DESIGN: A double-blinded, randomized, controlled trial. SETTING: Pre- and posttreatment assessments were performed in a gait laboratory, whereas stretching exercises were performed outside of the laboratory, usually in the subject's home. PARTICIPANTS: Eighty-two healthy elderly individuals, with 39 subjects in the control group and 43 subjects in the treatment group. INTERVENTION: The treatment group completed a 10-week, twice-daily hip flexor stretching program, which was supervised twice weekly by a rehabilitation clinician. The control group completed a 10-week shoulder abductor stretching program. MAIN OUTCOME MEASUREMENTS: Passive hip extension range of motion, dynamic peak hip extension, peak anterior pelvic tilt, stride length, and gait speed during walking. RESULTS: The treatment group showed significant improvements in passive hip extension range of motion (P = .007). Subjects in the treatment group who presented with limited preassessment peak hip extension during walking had increased stride length (P = .019) and peak hip extension (P = .012), and decreased anterior pelvic tilt (P = .006) during walking, whereas subjects in the control group showed only decreased anterior pelvic tilt (P = .013). CONCLUSIONS: The 10-week supervised hip flexor stretching program was effective in increasing stride length and peak hip extension during walking in elderly adults who had limited preintervention hip extension during walking. These results support the use of a simple stretching program for elderly individuals in counteracting age-related decline in gait function.

Effect of a supervised hip flexor stretching program on gait in frail elderly patients.

OBJECTIVE: To determine whether a 10-week supervised hip flexor stretching program in frail elderly subjects would increase peak hip extension, stride length, and gait speed and reduce anterior pelvic tilt during comfortable and fast-paced walking. DESIGN: A double-blinded, randomized, controlled trial. SETTING: Pre- and post-treatment assessments were performed in a gait laboratory and stretching exercises were performed outside of the laboratory, usually in the subjects' place of residence. PARTICIPANTS: Seventy-four frail elderly individuals, with 41 subjects in the control group and 33 subjects in the treatment group. INTERVENTION: The treatment group completed a 10-week twice-daily hip flexor stretching program that was supervised twice weekly by a rehabilitation clinician. The control group completed a 10-week shoulder abductor stretching program. MAIN OUTCOME MEASUREMENTS: Dynamic peak hip extension and peak anterior pelvic tilt, stride length, and gait speed while walking at a comfortable pace and a fast pace, as well as passive hip extension range of motion. RESULTS: The treatment group showed significant increases in walking speed and stride length after the intervention but showed no significant changes in peak hip extension or anterior pelvic tilt during comfortable and fast-paced walking. The treatment group also showed significantly increased passive hip extension range of motion. CONCLUSIONS: These results indicate that a simple stretching program is effective in improving some measures of age-related decline in gait function in frail elderly patients. The lack of consistent improvements in walking kinematics is attributed to the presence of multiple disabilities and limitations present in the frail subjects.

Effects of transcutaneous electrical nerve stimulation and therapeutic exercise on quadriceps activation in people with tibiofemoral osteoarthritis.

STUDY DESIGN: Blinded, randomized controlled trial. OBJECTIVES: To determine if the combination of transcutaneous electrical nerve stimulation (TENS) set to a sensory level and therapeutic exercise would be more effective than the combination of placebo TENS and therapeutic exercises or therapeutic exercises only to increase quadriceps activation in individuals with tibiofemoral osteoarthritis. BACKGROUND: Quadriceps activation deficits are common in those with tibiofemoral osteoarthritis, and TENS has been reported to immediately increase quadriceps activation. Yet the long-term benefits of TENS for motor neuron activation have yet to be determined. METHODS: Thirty-six individuals with radiographically assessed tibiofemoral osteoarthritis were randomly assigned to the TENS and exercise, placebo and exercise, and exercise only groups. All participants completed a supervised 4-week lower extremity exercise program. TENS and placebo TENS were worn throughout the therapeutic exercise sessions, as well as during daily activities. Our primary outcome measures, quadriceps central activation ratio, and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) were evaluated at baseline and at 2 weeks and 4 weeks of the intervention. RESULTS: Quadriceps activation was significantly higher in the TENS with exercise group compared to the exercise only group at 2 weeks (0.94 ± 0.04 versus 0.82 ± 0.12, P<.05) and the placebo and exercise group at 4 weeks (0.94 ± 0.06 versus 0.81 ± 0.15, P<.05). WOMAC scores improved in all 3 groups over time, with no significant differences among groups. CONCLUSION: This study provides evidence that TENS applied in conjunction with therapeutic exercise and daily activities increases quadriceps activation in patients with tibiofemoral osteoarthritis and, while function improved for all participants, effects were greatest in the group treated with a combination of TENS and therapeutic exercises. LEVEL OF EVIDENCE: Therapy, level 1b-.

Lower limb joint kinetics in walking: the role of industry recommended footwear.

The effects of current athletic footwear on lower extremity biomechanics are unknown. The aim of this study was to examine the changes, if any, that occur in peak lower extremity net joint moments while walking in industry recommended athletic footwear. Sixty-eight healthy young adults underwent kinetic evaluation of lower extremity extrinsic joint moments while walking barefoot and while walking in current standard athletic footwear matched to the foot mechanics of each subject while controlling for speed. A secondary analysis was performed comparing peak knee joint extrinsic moments during barefoot walking to those while walking in three different standard footwear types: stability, motion control, and cushion. 3-D motion capture data were collected in synchrony with ground reaction force data collected from an instrumented treadmill. The shod condition was associated with a 9.7% increase in the first peak knee varus moment, and increases in the hip flexion and extension moments. These increases may be largely related to a 6.5% increase in stride length with shoes associated with increases in the ground reaction forces in all three axes. The changes from barefoot walking observed in the peak knee joint moments were similar when subjects walked in all three footwear types. It is unclear to what extent these increased joint moments may be clinically relevant, or potentially adverse. Nonetheless, these differences should be considered in the recommendation as well as the design of footwear in the future.

Effects of disinhibitory transcutaneous electrical nerve stimulation and therapeutic exercise on sagittal plane peak knee kinematics and kinetics in people with knee osteoarthritis during gait: a randomized controlled trial.

OBJECTIVE: to determine whether sensory transcutaneous electrical nerve stimulation (TENS) augmented with therapeutic exercise and worn for daily activities for four weeks would alter peak gait kinetics and kinematics, compared with placebo electrical stimulation and exercise, and exercise only. DESIGN: randomized controlled trial. SETTING: motion analysis laboratory. SUBJECTS: thirty-six participants with radiographically assessed knee osteoarthritis and volitional quadriceps activation below 90% were randomly assigned to electrical stimulation, placebo and comparison (exercise-only) groups. INTERVENTIONS: participants in all three groups completed a four-week quadriceps strengthening programme directed by an experienced rehabilitation clinician. Active electrical stimulation units and placebo units were worn in the electrical stimulation and placebo groups throughout the rehabilitation sessions as well as during all activities of daily living. MAIN MEASURES: peak external knee flexion moment and angle during stance phase were analysed at a comfortable walking speed before and after the intervention. FINDINGS: Comfortable walking speed increased for all groups over time (TENS 1.16 ± 0.15 versus 1.32 ± 0.16 m/s; placebo 1.21 ± 0.34 versus 1.3 ± 0.24 m/s; comparison 1.27 ± 0.18 versus 1.5 ± 0.14 m/s), yet no group differences in speed were found. No differences were found for peak flexion moment or angle between groups overtime. CONCLUSIONS: TENS in conjunction with therapeutic exercise does not seem to affect peak flexion moment and angle during stance over a four-week period in participants with tibiofemoral osteoarthritis.

A three-dimensional kinematic and kinetic comparison of overground and treadmill walking in healthy elderly subjects.

BACKGROUND: Instrumented treadmills offer a number of advantages for the biomechanical analysis of elderly gait, yet it is unclear how closely treadmill gait approximates overground gait. Although studies have indicated that the kinematics and kinetics of overground and treadmill gait are very similar in young adults, it still needs to be determined whether data collected in elderly adults during treadmill walking can be generalized to overground gait. The purpose of this study, therefore, was to compare the three-dimensional kinematics and kinetics of treadmill gait to overground gait in a group of healthy elderly subjects. METHODS: Three-dimensional kinematic and kinetic data for 18 healthy, nondisabled elderly subjects, age 65-81 years, were collected for speed-matched overground and treadmill walking conditions. FINDINGS: Overall, the kinematics and kinetics of gait during treadmill and overground walking in the elderly had very similar patterns. However, during treadmill walking elderly subjects showed greater cadence, smaller stride length and stride time as well as reductions in the majority of joint angles, moments and powers when compared to overground walking. INTERPRETATION: The large increase in cadence suggests that an effective method of acclimation to treadmill walking still needs to be determined. Because of the differences, we believe that in order for instrumented treadmills to become a suitable tool for research and training purposes in healthy elderly, subjects must be adequately acclimated to the treadmill.

Lower limb joint kinetics during moderately sloped running.

CONTEXT: Knowledge of the kinetic changes that occur during sloped running is important in understanding the adaptive gait-control mechanisms at work and can provide additional information about the poorly understood relationship between injury and changes in kinetic forces in the lower extremity. A study of these potential kinetic changes merits consideration, because training and return-to-activity programs are potentially modifiable factors for tissue stress and injury risk. OBJECTIVE: To contribute further to the understanding of hill running by quantifying the 3-dimensional alterations in joint kinetics during moderately sloped decline, level, and incline running in a group of healthy runners. DESIGN: Crossover study. SETTING: Three-dimensional motion analysis laboratory. PATIENTS OR OTHER PARTICIPANTS: Nineteen healthy young runners/joggers (age = 25.3 +/- 2.5 years). INTERVENTION(S): Participants ran at 3.13 m/s on a treadmill under the following 3 different running-surface slope conditions: 4 degrees decline, level, and 4 degrees incline. MAIN OUTCOME MEASURE(S): Lower extremity joint moments and powers and the 3 components of the ground reaction force. RESULTS: Moderate changes in running-surface slope had a minimal effect on ankle, knee, and hip joint kinetics when velocity was held constant. Only changes in knee power absorption (increased with decline-slope running) and hip power (increased generation on incline-slope running and increased absorption on decline-slope running in early stance) were noted. We observed an increase only in the impact peak of the vertical ground reaction force component during decline-slope running, whereas the nonvertical components displayed no differences. CONCLUSIONS: Running style modifications associated with running on moderate slopes did not manifest as changes in 3-dimensional joint moments or in the active peaks of the ground reaction force. Our data indicate that running on level and moderately inclined slopes appears to be a safe component of training regimens and return-to-run protocols after injury.

Changes in hip joint muscle-tendon lengths with mode of locomotion.

We have reported that peak hip extension is nearly identical in walking and running, suggesting that anatomical constraints, such as flexor muscle tightness may limit the range of hip extension. To obtain a more mechanistic insight into mobility at the hip and pelvis we examined the lengths of the muscle-tendons units crossing the hip joint. Data defining the three-dimensional kinematics of 26 healthy runners at self-selected walking and running speeds were obtained. These data were used to scale and drive musculoskeletal models using OpenSIM. Muscle-tendon unit (MTU) lengths were calculated for the trailing limb illiacus, rectus femoris, gluteus maximus, and biceps femoris long head and the advancing limb biceps femoris and gluteus maximus. The magnitude and timing of MTU length peaks were each compared between walking and running. The peak length of the right (trailing limb) illiacus MTU, a pure hip flexor, was nearly identical between walking and running, while the maximum length of the rectus femoris MTU, a hip flexor and knee extensor, increased during running. The maximum length of the left (leading limb) biceps femoris was also unchanged between walking and running. Further, the timing of peak illiacus MTU length and peak contralateral biceps femoris MTU length occurred essentially simultaneously during running, at a time during gait when the hamstrings are most vulnerable to stretch injury. This latter finding suggests exploring the role for hip flexor stretching in combination with hamstring stretching to treat and/or prevent running related hamstring injury.

The effect of running shoes on lower extremity joint torques.

OBJECTIVE: To determine the effect of modern-day running shoes on lower extremity joint torques during running. DESIGN: Two-condition experimental comparison. SETTING: A 3-dimensional motion analysis laboratory. PARTICIPANTS: A total of 68 healthy young adult runners (37 women) who typically run in running shoes. METHODS: All subjects ran barefoot and in the same type of stability running footwear at a controlled running speed. Three-dimensional motion capture data were collected in synchrony with ground reaction force data from an instrumented treadmill for each of the 2 conditions. MAIN OUTCOME MEASUREMENTS: Peak 3-dimensional external joint torques at the hip, knee, and ankle as calculated through a full inverse dynamic model. RESULTS: Increased joint torques at the hip, knee, and ankle were observed with running shoes compared with running barefoot. Disproportionately large increases were observed in the hip internal rotation torque and in the knee flexion and knee varus torques. An average 54% increase in the hip internal rotation torque, a 36% increase in knee flexion torque, and a 38% increase in knee varus torque were measured when running in running shoes compared with barefoot. CONCLUSIONS: The findings at the knee suggest relatively greater pressures at anatomical sites that are typically more prone to knee osteoarthritis, the medial and patellofemoral compartments. It is important to note the limitations of these findings and of current 3-dimensional gait analysis in general, that only resultant joint torques were assessed. It is unknown to what extent actual joint contact forces could be affected by compliance that a shoe might provide, a potentially valuable design characteristic that may offset the observed increases in joint torques.

Altered ankle kinematics and shank-rear-foot coupling in those with chronic ankle instability.

CONTEXT: Kinematic patterns during gait have not been extensively studied in relation to chronic ankle instability (CAI). OBJECTIVE: To determine whether individuals with CAI demonstrate altered ankle kinematics and shank-rear-foot coupling compared with controls during walking and jogging. DESIGN: Case control. SETTING: Motion-analysis laboratory. PARTICIPANTS: 7 participants (3 men, 4 women) suffering from CAI (age 24.6 +/- 4.2 y, height 172.6 +/- 9.4 cm, mass 70.9 +/- 8.1 kg) and 7 (3 men, 4 women) healthy, matched controls (age 24.7 +/- 4.5 y, height 168.2 +/- 5.9 cm, mass 66.5 +/- 9.8 kg). INTERVENTIONS: Subjects walked and jogged on a treadmill while 3-dimensional kinematics of the lower extremities were captured. MAIN OUTCOME MEASURES: The positions of rear-foot inversion-eversion and shank rotation were calculated throughout the gait cycle. Continuous relative-phase angles between these segments were calculated to assess coupling. RESULTS: The CAI group demonstrated more rear-foot inversion and shank external rotation during walking and jogging. There were differences between groups in shank-rear-foot coupling during terminal swing at both speeds. CONCLUSIONS: Altered ankle kinematics and joint coupling during the terminal-swing phase of gait may predispose a population with CAI to ankle-inversion injuries. Less coordinated movement during gait may be an indication of altered neuromuscular recruitment of the musculature surrounding the ankle as the foot is being positioned for initial contact.

Jogging kinematics after lumbar paraspinal muscle fatigue.

CONTEXT: Isolated lumbar paraspinal muscle fatigue causes lower extremity and postural control deficits. OBJECTIVE: To describe the change in body position during gait after fatiguing lumbar extension exercises in persons with recurrent episodes of low back pain compared with healthy controls. DESIGN: Case-control study. SETTING: Motion analysis laboratory. PATIENTS OR OTHER PARTICIPANTS: Twenty-five recreationally active participants with a history of recurrent episodes of low back pain, matched by sex, height, and mass with 25 healthy controls. INTERVENTION(S): We measured 3-dimensional lower extremity and trunk kinematics before and after fatiguing isometric lumbar paraspinal exercise. MAIN OUTCOME MEASURE(S): Measurements were taken while participants jogged on a custom-built treadmill surrounded by a 10-camera motion analysis system. RESULTS: Group-by-time interactions were observed for lumbar lordosis and trunk angles (P < .05). A reduced lumbar spine extension angle was noted, reflecting a loss of lordosis and an increase in trunk flexion angle, indicating increased forward trunk lean, in healthy controls after fatiguing lumbar extension exercise. In contrast, persons with a history of recurrent low back pain exhibited a slight increase in spine extension, indicating a slightly more lordotic position of the lumbar spine, and a decrease in trunk flexion angles after fatiguing exercise. Regardless of group, participants experienced, on average, greater peak hip extension after lumbar paraspinal fatigue. CONCLUSIONS: Small differences in response may represent a necessary adaptation used by persons with recurrent low back pain to preserve gait function by stabilizing the spine and preventing inappropriate trunk and lumbar spine positioning.

Differences in static and dynamic measures in evaluation of talonavicular mobility in gait.

STUDY DESIGN: Controlled laboratory study using a cross-sectional design. OBJECTIVES: To compare the measurements of navicular drop during walking and running to those made clinically during a static position in a group of healthy young adults. BACKGROUND: The navicular drop test is a common clinical measure of foot structure and, more specifically, of talonavicular joint function. Previous work has focused on static measurement to establish the relationship between navicular drop and various overuse injuries. However, loads on foot structure are dramatically increased during gait. Examining navicular drop dynamically is more reflective of the functional demands of the foot when walking and running. METHODS: The navicular drop of 72 healthy runners was evaluated using 2 static methods. Results were used to classify individuals into groups and compared to dynamic measures of navicular drop made during walking and running. Three-dimensional motion capture and an instrumented treadmill were used to assess dynamic navicular mobility. A repeated-measures analysis of variance (ANOVA) was performed to examine differences between measurement conditions. Between-group differences were assessed with independent-samples t test (P<.05). RESULTS: Static measures of navicular drop were not found to be uniformly predictive of dynamic function during walking or running. Functional navicular drop measurements underestimated the dynamic measures in all foot types, while subtalar neutral drop overestimated dynamic measures for individuals with neutral and hypermobile foot types. No differences in navicular drop were found between foot types during walking, and small differences were found in running only between the hypomobile and hypermobile foot types. Maximum foot deformation during gait occurs at the time of maximum ground reaction force. Significant differences in navicular drop between foot type groups measured statically become muted when looking at group differences while walking and running. CONCLUSIONS: Differences in navicular mobility between foot type groups during walking and running indicate that factors other than static alignment affect dynamic foot mobility. Dynamic assessment of navicular mobility may be an effective tool to examine the interplay of how the extrinsic force demands of gait and intrinsic structure and neuromuscular control affect foot function in walking and running.

Effects of balance training on gait parameters in patients with chronic ankle instability: a randomized controlled trial.

OBJECTIVE: To examine the effects of a four-week balance training programme on ankle kinematics during walking and jogging in those with chronic ankle instability. A secondary objective was to evaluate the effect of balance training on the mechanical properties of the lateral ligaments in those with chronic ankle instability. DESIGN: Randomized controlled trial. SETTING: Laboratory. SUBJECTS/PATIENTS: Twenty-nine participants (12 males, 17 females) with self-reported chronic ankle instability were randomly assigned to a balance training group or a control group. INTERVENTION: Four weeks of supervised rehabilitation that emphasized dynamic balance stabilization in single-limb stance. The control group received no intervention. MAIN OUTCOME MEASURES: Kinematic measures of rearfoot inversion/eversion, shank rotation, and the coupling relationship between these two segments throughout the gait cycle during walking and jogging on a treadmill. Instrumented ankle arthrometer measures were taken to assess anterior drawer and inversion talar tilt laxity and stiffness. RESULTS: No significant alterations in the inversion/eversion or shank rotation kinematics were found during walking and jogging after balance training. There was, however, a significant decrease in the shank/rearfoot coupling variability during walking as measured by deviation phase after balance training (balance training posttest: 13.1 degrees +/- 6.2 degrees , balance training pretest: 16.2 degrees +/- 3.3 degrees , P = 0.03), indicating improved shank/rearfoot coupling stability. The control group did not significantly change. (posttest: 16.30 degrees +/- 4.4 degrees , pretest: 18.6 degrees +/- 7.1 degrees , P40.05) There were no significant changes in laxity measures for either group. CONCLUSIONS: Balance training significantly altered the relationship between shank rotation and rearfoot inversion/eversion in those with chronic ankle instability.

Changes in the coordination of hip and pelvis kinematics with mode of locomotion.

Limited hip extension mobility has been proposed as a possible cause of both increased anterior pelvic tilt and subsequent exaggerated lumbar lordosis during walking and running. The purpose of the present study was to examine the coordinated sagittal plane kinematic patterns of the hip and pelvis during walking and running in a substantial group of adult recreational runners. The kinematics of 73 healthy adult runners (age: 34+/-11years) were examined on an instrumented treadmill at self-selected walking and running speeds using a three-dimensional motion capture system. Although stride length increased considerably from walking to running, the range of hip extension utilized during running was not significantly greater than that during walking. Thigh extension and anterior pelvic tilt were significantly greater during running than walking. Also, a significant positive correlation was found between hip extension and anterior pelvic tilt during both walking and running, indicating that anterior pelvic tilt was greater in subjects that displayed reduced utilized peak hip extension. Thus, compensations for the increased stride length during running seem to occur at the pelvis, and presumably in the lumbar spine, rather than at the hip. Considering the association between anterior pelvic tilt and lumbar lordosis, the present findings may have clinical relevance regarding the prevention and treatment of hamstring injuries and of injuries to the lumbar spine.