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Michal N. Glinka, Kim P. Cheema, Stephen N. Robinovitch and Andrew C. Laing

Safety floors (also known as compliant floors) may reduce the risk of fall-related injuries by attenuating impact force during falls, but are only practical if they do not negatively affect balance and mobility. In this study, we evaluated seven safety surfaces based on their ability to attenuate peak femoral neck force during simulated hip impacts, and their influence on center of pressure (COP) sway during quiet and tandem stance. Overall, we found that some safety floors can attenuate up to 33.7% of the peak femoral impact force without influencing balance. More specifically, during simulated hip impacts, force attenuation for the safety floors ranged from 18.4 (SD 4.3)% to 47.2 (3.1)%, with each floor significantly reducing peak force compared with a rigid surface. For quiet stance, only COP root mean square was affected by flooring (and increased for only two safety floors). During tandem stance, COP root mean square and mean velocity increased in the medial-lateral direction for three of the seven floors. Based on the substantial force attenuation with no concomitant effects on balance for some floors, these results support the development of clinical trials to assess the effectiveness of safety floors at reducing fall-related injuries in high-risk settings.

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Zheng Wang, Kimberlee Jordan and Karl M. Newell

In this study, two force platforms were synchronized to investigate the coordination of the right and left foot center of pressure (COPR and COPL) and its relation to the COPNET in the control of 5 upright postures with and without visual information. The results revealed that the standard deviation (SD) of COPL, COPR, and COPNET progressively increased in the more challenging staggered and tandem stances, respectively, and to a lesser degree with the absence of visual information. Circular analysis of the relative phase of COPL and COPR revealed that the coupling pattern and variability were dependent on postural stances and the availability of vision. A negative correlation between the variability of the relative phase of the two feet COPs and the SD of the COPNET in the anterior-posterior (AP) direction was evident most strongly in the no vision conditions. Thus, the asymmetry of the mechanical constraints on the feet as a function of stance organize the coordination patterns of the feet COPs while the degree of adaptive variation between the feet COPs is dependent on both the mechanical constraints and the availability of vision.

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Michael D. Lewek, Claire E. Bradley, Clinton J. Wutzke and Steven M. Zinder

Falls are common after stroke and often attributed to poor balance. Falls often occur during walking, suggesting that walking patterns may induce a loss of balance. Gait after stroke is frequently spatiotemporally asymmetric, which may decrease balance. The purpose of this study is to determine the relationship between spatiotemporal gait asymmetry and balance control. Thirty-nine individuals with chronic stroke walked at comfortable and fast speeds to calculate asymmetry ratios for step length, stance time, and swing time. Balance measures included the Berg Balance Scale, step width during gait, and the weight distribution between legs during standing. Correlational analyses determined the relationships between balance and gait asymmetry. At comfortable and fast gait speeds, step width was correlated with stance time and swing time asymmetries (r = 0.39−0.54). Berg scores were correlated with step length and swing time asymmetries (r = –0.36 to –0.63). During fast walking, the weight distribution between limbs was correlated with stance time asymmetry (r = –0.41). Spatiotemporal gait asymmetry was more closely related to balance measures involving dynamic tasks than static tasks, suggesting that gait asymmetry may be related to the high number of falls poststroke. Further study to determine if rehabilitation that improves gait asymmetry has a similar influence on balance is warranted.

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Matthew J. Moncrieff and Lori A. Livingston

Context:

Structural and coronal-plane-alignment characteristics of the lower limb are frequently cited as factors contributing to knee pathologies.

Objective:

The purpose of this study was to determine the accuracy and reliability characteristics of a digital-photographic-goniometric method (DPGM) of measurement for 2-dimensional (2D) coronal-plane lower limb measurements of the quadriceps (Q) angle, tibiofemoral (TF) angle, and femur length in human participants adopting a self-selected- or Romberg-stance position.

Design:

Reliability study.

Setting:

University motion-analysis laboratory.

Participants:

A convenience sample of 20 healthy young adult men and women.

Main Outcome Measures:

Intraclass correlation coefficients (ICCs), 95% confidence intervals, and standard error of the measurements.

Results:

Intratester- and intertester-reliability coefficients for the Q angle (ICCs .458–845 and .257–737) were consistently lower than those for the TF angle (ICCs .627–.904 and .700–.839) or femur length (ICCs .867–.958 and .866–.944). Q angles were also significantly larger (13.4%) in the Romberg- vs self-selected-stance position (P < .001) and larger (20.2%) in the left limb than the right limb.

Conclusions:

The DPGM has the potential to produce accurate and reliable measurements of selected 2D lower limb measures. However, the reliability characteristics depend on the ability of the testers to correctly and repeatably landmark the anatomical sites used to define the measurements of interest and might be influenced by other factors such as the stance position adopted, the complexity of the variable (ie, number of anatomical landmarks and segments), and the size of the captured image. Further investigation of these latter factors is warranted.

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Kyung-Min Kim, Christopher D. Ingersoll and Jay Hertel

Context:

Focal ankle-joint cooling (FAJC) has been shown to increase Hoffmann (H) reflex amplitudes of select leg muscles while subjects lie prone, but it is unknown whether the neurophysiological cooling effects persist in standing.

Objective:

To assess the effects of FAJC on H-reflexes of the soleus and fibularis longus during 3 body positions (prone, bipedal, and unipedal stances) in individuals with and without chronic ankle instability (CAI).

Design:

Crossover.

Setting:

Laboratory.

Participants:

15 young adults with CAI (9 male, 6 female) and 15 healthy controls.

Intervention:

All subjects received both FAJC and sham treatments on separate days in a randomized order. FAJC was accomplished by applying a 1.5-L plastic bag filled with crushed ice to the ankle for 20 min. Sham treatment involved room-temperature candy corn.

Main Outcome Measures:

Maximum amplitudes of H-reflexes and motor (M) waves were recorded while subjects lay prone and then stood in quiet bipedal and unipedal stances before and immediately after each treatment. Primary outcome measures were Hmax:Mmax ratios for the soleus and fibularis longus. Three-factor (group × treatment condition × time) repeated-measures ANOVAs and Fisher LSD tests were performed for statistical analyses.

Results:

Significant interactions of treatment condition by time for prone Hmax:Mmax ratios were found in the soleus (P = .001) and fibularis longus (P = .003). In both muscles, prone Hmax:Mmax ratios moderately increased after FAJC but not after sham treatment. The CAI and healthy groups responded similarly to FAJC. In contrast, there were no significant interactions or main effects in the bipedal and unipedal stances in either muscle (P > .05).

Conclusions:

FAJC moderately increased H-reflex amplitudes of the soleus and fibularis longus while subjects were prone but not during bipedal or unipedal standing. These results were not different between groups with and without CAI.

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Matthew C. Hoch, David R. Mullineaux, Richard D. Andreatta, Robert A. English, Jennifer M. Medina-McKeon, Carl G. Mattacola and Patrick O. McKeon

Context:

A single talocrural joint-mobilization treatment has improved spatiotemporal measures of postural control but not ankle arthrokinematics in individuals with chronic ankle instability (CAI). However, the effects of multiple treatment sessions on these aspects of function have not been investigated.

Objective:

To examine the effect of a 2-wk anterior-to-posterior joint-mobilization intervention on instrumented measures of single-limb-stance static postural control and ankle arthrokinematics in adults with CAI.

Design:

Repeated measures.

Setting:

Research laboratory.

Participants:

12 individuals with CAI (6 male, 6 female; age 27.4 ± 4.3 y, height 175.4 ± 9.78 cm, mass 78.4 ± 11.0 kg).

Intervention:

Subjects received 6 treatments sessions of talocrural grade II joint traction and grade III anterior-to-posterior joint mobilization over 2 wk.

Main Outcome Measures:

Instrumented measures of single-limb-stance static postural control (eyes open and closed) and anterior and posterior talar displacement and stiffness were assessed 1 wk before the intervention (baseline), before the first treatment (preintervention), 24–48 h after the final treatment (postintervention), and 1 wk later (1-wk follow-up). Postural control was analyzed as center-of-pressure velocity, center-of-pressure range, the mean of time-to-boundary minima, and standard deviation of time-to-boundary minima in the anteroposterior and mediolateral directions for each visual condition.

Results:

No significant differences were identified in any measures of postural control (P > .08) or ankle arthrokinematics (P > .21).

Conclusions:

The 2-wk talocrural joint-mobilization intervention did not alter instrumented measures of single-limb-stance postural control or ankle arthrokinematics. Despite the absence of change in these measures, this study continues to clarify the role of talocrural joint mobilization as a rehabilitation strategy for patients with CAI.

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Justin M. Stanek, John Meyer and Rob Lynall

Context:

Balance training is widely used by rehabilitation professionals and has been shown to be effective at reducing risk of injury, as well as improving function after injury. However, objective evidence for the difficulty of commonly available equipment is lacking.

Objective:

To assess center-of-pressure (COP) area and average sway velocity in healthy subjects while performing a single-limb stance on 4 commonly available rehabilitation devices to determine their level of difficulty.

Design:

Single-session, randomized, repeated-measures design to assess COP area and average sway velocity while performing a single-limb stance on 4 devices positioned on a force platform.

Setting:

University laboratory.

Subjects:

A convenience sample of 57 healthy college-age subjects.

Intervention:

Each participant balanced on the dominant limb in a nonshod single-limb stance with eyes open for 20 s during 4 conditions. The 4 conditions were randomized and included the Both Sides Up (BOSU) trainer, Airex balance pad, half-foam roller, and DynaDisc.

Main Outcome Measure:

Means and standard deviations were calculated for maximum displacement in each direction. In addition, the means and standard deviations for COP area and average sway velocity were calculated for the 4 conditions and compared using a 1-way repeated-measure ANOVA.

Results:

Significant differences were found for both COP area and average sway velocity between the BOSU trainer and the other 3 devices. A significant difference was also found between the DynaDisc and the half-foam roller.

Conclusions:

Level of difficulty, as measured by COP area and average sway velocity, is different for commonly available rehabilitation equipment. Clinicians may find these results a useful guide when progressing patients through balance training.

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Karen P. DePauw and Gudrun Doll-Tepper

Inclusion has been a topic of discussions and debate among adapted physical activity professionals since the 1980s. Although the initial discussions focused primarily on inclusion as a place or placement, the discourse today about inclusion must be expanded to incorporate issues of context, disability rights, and social justice. Inclusion must now be reconceptualized as an attitude or a process. Progressive inclusion and acceptance is not a myth but a reality. As international attention and efforts are focused on physical education as a right of all children, APA professionals must forego bandwagons and adopt a strong philosophical stance that guides our efforts toward achieving inclusive physical education.

Open access

Matthew C. Hoch, David R. Mullineaux, Kyoungkyu Jeon and Patrick O. McKeon

Single joint kinematic alterations have been identified during gait in those with chronic ankle instability (CAI). The purpose of this study was to compare sagittal plane hip, knee, and ankle kinematics during walking in participants with and without CAI. Twelve individuals with CAI and 12 healthy individuals walked on a treadmill at 1.5 m/s. Three-dimensional kinematics were analyzed using mean ensemble curves and independent t tests. Participants with CAI demonstrated less lower extremity flexion during the absorption phase of stance and the limb placement phase of swing, which may have implications for limb placement at initial contact.

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Dana Forrest, Janet S. Dufek and John A. Mercer

The purpose of this study was to determine if ground reaction forces were influenced by shoe design (adult vs. youth) for female children when running. Subjects (n = 10, 12.0 ± 1.1 years old; 154 ± 4.9 cm; 46.2 ± 14.3 kg; shoe size 3.5–7 youth) were fit with a shoe model available in youth and adult sizes. Subjects ran 10 trials per shoe condition across a force platform placed in the middle of a 9-m runway. Impact force, second maximum force, loading rate, stance time and average vertical ground reaction forces were recorded for each trial. Shoes underwent a mechanical impact test with peak force, peak acceleration, and percent energy returned recorded. Each variable was compared between shoe conditions. From the impact testing, it was determined that peak force, peak acceleration and percent energy return were 7.1%, 7.1%, and 18.9% greater, respectively, for the youth vs. adult shoe (p < .001). From the running tests, it was determined that loading rate was different (p = .009) between shoe conditions whereas impact force, second maximum force, average force and stance time were not different between shoes (p > .01). Young girls had a greater loading rate when running in youth vs. adult shoes even though the shoe size was the same.