single limb from each subject (Figure 1 ). In order to avoid effects of intervention order and/or limb dominance, the treatment order was counterbalanced with 7 subjects having the stance leg treated first and the remaining 6 subjects receiving treatment on the skill leg first, the skill leg defined as
Max Pietrzak and Niels B.J. Vollaard
Becky L. Heinert, Thomas W. Kernozek, John F. Greany and Dennis C. Fater
To determine if females with hip abductor weakness are more likely to demonstrate greater knee abduction during the stance phase of running than a strong hip abductor group.
Observational prospective study design.
University biomechanics laboratory.
15 females with weak hip abductors and 15 females with strong hip abductors.
Main Outcome Measures:
Group differences in lower extremity kinematics were analyzed using repeated measures ANOVA with one between factor of group and one within factor of position with a significance value of P < .05.
The subjects with weak hip abductors demonstrated greater knee abduction during the stance phase of treadmill running than the strong group (P < .05). No other significant differences were found in the sagittal or frontal plane measurements of the hip, knee, or pelvis.
Hip abductor weakness may influence knee abduction during the stance phase of running.
Bryan L. Riemann, Kevin M. Guskiewicz and Edgar W. Shields
Although sophisticated forceplate systems are available for postural stability analyses, their use is limited in many sports medicine settings because of budgetary constraints. The purpose of this investigation was to compare a clinical method of evaluating postural stability with a force-platform sway measure. Participants completed a battery of three stance variations (double, single, and tandem) on two different surfaces (firm and foam) while standing on a force platform. This arrangement allowed for simultaneous comparisons between forceplate sway measures and clinical assessments using the Balance Error Scoring System (BESS). Significant correlations were revealed for the single-leg and tandem stances on the firm surface and for double, single, and tandem stances on the foam surface. These results suggest that the BESS is a reliable method of assessing postural stability in the absence of computerized balance systems.
Beth Jamali, Martha Walker, Brian Hoke and John Echternach
Windlass taping is used to reduce pain in plantar fasciitis and thought to take stress off the plantar fascia.
To investigate the effects of windlass taping.
Single group, repeated measures.
Outpatient physical therapy clinics.
20 subjects with plantar fasciitis.
Windlass taping technique.
Main Outcome Measures:
Pretaping and posttaping measures included pain levels using a visual analog scale (VAS), resting-stance calcaneal position, tibial position, and navicular height. Fifteen also reported a VAS after wearing the tape for 24 h.
Median VAS score 37 mm pretape and 6 mm immediately posttape and 24 h later. Wilcoxon matched-pairs signed ranks test significant (P = .001) for reduction in pain scores. Paired t tests significant (P = .01) for a difference between means of pretaping and posttaping measurements for resting-stance positions.
Windlass taping decreased pain in patients with plantar fasciitis and caused small changes in resting-stance positions.
Thomas A. Stoffregen, Philip Hove, Jennifer Schmit and Benoît G. Bardy
We demonstrated that postural responses to imposed optic flow are to some extent voluntary. In a moving room, participants either stood normally or were instructed to resist any influence of visible motion on their stance. When participants attempted to resist, coupling of body sway with motion of the room was significantly greater than when the eyes were closed, but was significantly reduced relative to coupling in the normal stance condition. The results indicate that the use of imposed optic flow for postural control is not entirely automatic or involuntary. This conclusion motivates a search for non-perceptual factors that may influence the degree to which body sway is coupled to imposed optic flow.
Jonathon R. Staples, Kevin A. Schafer, Matthew V. Smith, John Motley, Mark Halstead, Andrew Blackman, Amanda Haas, Karen Steger-May, Matthew J. Matava, Rick W. Wright and Robert H. Brophy
current lower-extremity symptoms or limitations or any previous lower-extremity surgery. Procedures All subjects underwent double-leg stance dynamic postural stability testing using the PROPRIO ® 5000 Reactive Balance System by Perry Dynamics (Decatur, IL) 27 – 30 (Figure 1 ) on a multidirectional
Michael Sanders, Anton E. Bowden, Spencer Baker, Ryan Jensen, McKenzie Nichols and Matthew K. Seeley
requirements for the left leg during terminal stance and initial ground contact, respectively. Based on these results, we expect the following muscular adaptations for traditional crutch ambulation regarding EMG for ambulation involving traditional crutches: hypertrophy or at least muscle mass maintenance for
Kristian M. O’Connor and Joseph Hamill
The ankle joint has typically been treated as a universal joint with moments calculated about orthogonal axes and the frontal plane moment generally used to represent the net muscle action about the subtalar joint. However, this joint acts about an oblique axis. The purpose of this study was to examine the differences between joint moments calculated about the orthogonal frontal plane axis and an estimated subtalar joint axis. Three-dimensional data were colected on 10 participants running at 3.6 m/s. Joint moments, power, and work were calculated about the orthogonal frontal plane axis of the foot and about an oblique axis representing the subtalar joint. Selected parameters were compared with a paired t-test (α = 0.05). The results indicated that the joint moments calculated about the two axes were characteristically different. A moment calculated about an orthogonal frontal plane axis of the foot resulted in a joint moment that was invertor in nature during the first half of stance, but evertor during the second half of stance. The subtalar joint axis moment, however, was invertor during most of the stance. These two patterns may result in qualitatively different interpretations of the muscular contributions at the ankle during the stance phase of running.
Jacob Buus Andersen and Thomas Sinkjaer
Due to the complexity of applying a well-defined stretch during human walking, most of our knowledge about the short latency stretch reflex modulation in humans is based on H-reflex studies. To illuminate the difference between the two methodologies, both types of reflexes were evoked in the same subjects, same experiment. Stretch reflexes were evoked via a stretch device capable of evoking stretch reflexes of the human soleus muscle during walking. H-reflexes were elicited by an electrical stimulation of the tibial nerve at the popliteal fossa at the knee. A significantly different modulation of the two reflexes was found in the late stance where the stretch reflex decreased in relation to the H-reflex. This was consistent with an unloading of the muscle spindles during the push-off in late stance, suggesting a complex alpha-gamma coactivation, if any, at this time of the step. The soleus stretch reflex and H-reflex were compared during the stance phase of walking and sitting at matched soleus EMG activity. No difference was found in the amplitude of the stretch reflex. However, there was a significant decrease of the H-reflex during the stance phase of walking, consistent with a task-specific presynaptic mediated reflex control. It is proposed that the short latency stretch reflex during walking is not sensitive to such a presynaptic inhibition.
Pedro Rodrigues, Ryan Chang, Trampas TenBroek, Richard van Emmerik and Joseph Hamill
Excessive pronation, because of its coupling with tibial internal rotation (TIR), has been implicated as a risk factor in the development of anterior knee pain (AKP). Traditionally, this coupling has been expressed as a ratio between the eversion range of motion and the TIR range of motion (Ev/TIR) that occurs during stance. Currently, this technique has not been used to evaluate specific injuries or the effects of sex. In addition, Ev/TIR is incapable of detecting coupling changes that occur throughout stance. Therefore, the purpose of this study was to compare the coupling between eversion and TIR in runners with (n = 19) and without AKP (n = 17) and across sex using the Ev/TIR ratio, and more continuously using vector coding. When using vector coding, significant coupling differences were noted in runners with AKP (34% to 38% stance), with runners with AKP showing relatively more TIR than eversion. Similarly significant differences were noted across sex (14%–25% and 36%–47% stance), with males transitioning from a loading to propulsive coordination pattern using a proximal to distal strategy, and female runners using a distal to proximal strategy. These differences were only detected when evaluating this coupling relationship using a continuous technique such as vector coding.