Impact of bilateral motion control shoes with outsole adjustment on gait asymmetry in individuals with mild leg length discrepancy.

BACKGROUND: Footwear adjustment is recommended in the management plan of leg length discrepancy. However, it is not clear how the outsole of motion control shoe adjustment influences trunk symmetry and walking performance. RESEARCH QUESTION: Does bilateral adjustment of the outsole affect trunk and pelvis symmetry and ground reaction force during walking in individuals with leg length discrepancy? METHODS: 20 mild leg length discrepancy participants were recruited into a cross-sectional study. All subjects performed a walking trial with their habitual shoes to determine the outsole adjustment. Four trials of walking were carried out in the order of unadjusted and bilateral adjusted motion control air-cushion shoes. Shoulder level differences and trunk and pelvic motion were assessed, while the ground reaction force at the heel strike was reported. A paired t-test was performed to compare the differences between the conditions with a significance level at p < 0.05. RESULTS: During walking trials, mild leg length discrepancy participants with the adjusted shoe displayed lower variations in the maximum shoulder height differences (p = 0.001) and trunk rotation angle (p = 0.002) than those with the unadjusted shoe. Also, there was a significant reduction in the vertical ground reaction force (p = 0.030), but not in the anteroposterior or mediolateral directions, during walking in the adjusted shoe condition compared to the unadjusted shoe condition. SIGNIFICANCE: The outsole adjustment of the bilateral motion control shoes can improve trunk symmetry while decreasing the ground impact at the heel strike. The study provides additional information to prescribe or recommend footwear adjustment to improve walking symmetry in leg length discrepancy participants.

The Influence of Kinesio Tape and an Ankle Brace on the Lower Extremity Joint Motion in Fatigued, Unstable Ankles during a Lateral Drop Landing.

BACKGROUND: An unstable ankle along with plantar flexor muscle fatigue may exacerbate landing performance. External support may be an option to control the ankle motion and protect joints from injuries. Research goal: To investigate the immediate changes in the joint motion of a lower extremity under ankle plantar flexors fatigue conditions in athletes with unstable ankles using different external supports. METHODS: A total of 44 participants were allocated to a control (Cn) group, an ankle brace (AB) group, and a kinesio tape (KT) group, and were asked to perform a lateral drop landing before and after a fatigue protocol. The outcome measures were fatigue-induced changes in the maximal joint angle and changes in the angle ranges of the hip, knee, and ankle. RESULTS: Smaller changes in the maximal hip abduction were found in the AB group (p = 0.025), and the KT group exhibited smaller changes in the maximal ankle dorsiflexion (p = 0.009). The AB group landed with a smaller change in the range of hip flexion and knee flexion (p = 0.008 and 0.006). The Cn group had greater fatigue-induced changes in the COM range than AB and KT group (p = 0.002 and 0.028). SIGNIFICANCE: Despite the beneficial effect in the postural control in the frontal plane, the use of AB might constrain the distal joint motion which might lead to an extended knee landing posture resulting in secondary injuries to the knee joint. Therefore, the use of AB in conjunction with an additional training of landing strategy might be recommended from the injury prevention perspective.

Effects of Different Ankle Supports on the Single-Leg Lateral Drop Landing Following Muscle Fatigue in Athletes with Functional Ankle Instability.

BACKGROUND: Ankle support has been utilized for athletes with functional ankle instability (FAI), however, its effect on the landing performance during muscle fatigue is not well understood. This study aimed to examine the effects of ankle supports (ankle brace vs. Kinesio tape) on athletes with FAI following fatigued single-leg landing. METHODS: Thirty-three young FAI athletes (CAIT scores < 24) were randomly allocated to control (Cn), ankle brace (AB) and Kinesio tape (KT) groups. All athletes performed single-leg lateral drop landings following ankle fatigue protocol. The fatigue-induced changes in kinetic parameters were measured among three groups. RESULTS: A significant increase in peak vertical ground reaction force (vGRF) was found in the AB group (0.12% body weight (BW)) compared to that of the KT (0.02% BW) and Cn (median = 0.01% BW) groups. Significant decrease in both COP medial-lateral (ML) and anterior-posterior (AP) ranges were also found in the KT group (median = -0.15% foot width (FW) & median = -0.28% foot length (FL)) than those of the Cn group (median = 0.67% FW& median = 0.88% FL). CONCLUSIONS: Ankle braces might hamper the ability to absorb the impact force during landing. On the other hand, Kinesio tape might be beneficial for the postural control during landing.

Differences of ballet turns (pirouette) performance between experienced and novice ballet dancers.

PURPOSE: This study investigated the different postural control strategies exhibited by experienced and novice dancers in ballet turns (pirouettes). METHOD: Thirteen novice and 13 experienced dancers performed ballet turns with dominant-leg support. The peak push force was measured in the double-leg support phase. The inclination angles of rotation axis with respect to vertical axis were calculated in the early single-leg support phase as well as the initiation sequence of ankle, knee, and hip joints on the supporting leg. Moreover, the anchoring index of the head was computed in the transverse plane during turning. RESULTS: The novice dancers applied a greater push force, an increased inclination angle of rotation axis, and an insufficient proximal-to-distal extension sequence pattern. The novice dancers also had a smaller head-anchoring index compared with experienced dancers, which meant novice dancers were not using a space target as a stability reference. CONCLUSIONS: A poorer performance in novice dancers could result from higher push force in propulsion, lack of a "proximal-to-distal extension sequence" pattern, and lack of visual spotting for postural stability. Training on sequential initiation of lower-extremity joints and rehearsal of visual spotting are essential for novice dancers to obtain better performance on ballet turns.

Effect of impeded medial longitudinal arch drop on vertical ground reaction force and center of pressure during static loading.

BACKGROUND: Arch supports commonly used to alleviate foot pain can impede the normal drop of medial longitudinal arch (MLA) thereby altering its function. The purpose of the study was to examine the effect of using arch supports on vertical ground reaction force (GRF) and center of pressure (COP) during simulated midstance while the foot was statically loaded. MATERIALS AND METHOD: Ten healthy young subjects were recruited. Two dimensional (2D) analysis of the MLA was captured for both barefoot (BF) and arch support conditions before and after loading via a custom made weight loading apparatus. The foot was loaded and positioned to simulate the midstance phase of walking. Two-dimensional reflective markers demarcated the MLA and captured with the loaded foot on a force platform. The impeded MLA drop was compared between the unloaded BF, loaded BF and loaded arch support conditions. The vertical GRF, the anterior-posterior and the medial-lateral COP displacements were also measured in response to the impeded MLA by the arch supports. RESULTS: The arch supports impeded the MLA drop (p<0.05) and shifted the COP toward the medial side (p<0.05), specifically for the rearfoot (calcaneal segment region), but no changes were determined for the vertical GRF (p>0.05). CONCLUSION: The impedance of MLA drop by the arch support altered the pattern of the ML COP shift in the rearfoot region. CLINICAL RELEVANCE: The use of arch supports may not relieve painful foot conditions that are associated with excessive calcaneal eversion indicated by altering COP shifts in localized foot regions.

Soft-tissue movement at the foot during the stance phase of walking.

BACKGROUND: soft-tissue movement has challenged the use of noninvasive skin-based markers that are assumed to be rigidly attached to the underlying bony landmarks. We assessed soft-tissue movement in multiple foot segments by calculating the relative changes in the intermarker distances of the hindfoot, midfoot, and forefoot segments during the early, middle, and late stances of walking compared with the intermarker distances measured while participants remained still during standing. METHODS: seven healthy young adults with no previous lower-limb injury were tested while walking barefoot at a comfortable pace. Skin-based markers were placed on three foot regions (hindfoot-calcaneus, midfoot-navicular, and forefoot-first to fifth metatarsals). A motion system sampled at 120 Hz was used to capture the foot markers during the stance phase of walking. RESULTS: soft-tissue movement was found in the forefoot region characterized by shortened distances, specifically during early (breaking) stance and late (propulsion) stance. In the hindfoot region, soft-tissue movement was characterized by shortened and elongated distances during the early and late stance periods, respectively. All of the foot regions showed the least intermarker distance changes during midstance. CONCLUSIONS: the dynamics of soft-tissue movement in multiple foot segments were characterized by the greatest changes in the intermarker distances in the forefoot and hindfoot during the early and late stance phases and the least changes in the foot segments during midstance. The results provide a feasible and accessible measurement for assessing soft-tissue movement in the foot when skin-based motion markers are used.

Bilateral claudication results in alterations in the gait biomechanics at the hip and ankle joints.

Claudication is the most common symptomatic manifestation of peripheral arterial disease (PAD), producing significant ambulatory compromise. The purpose of this study was to use advanced biomechanical gait analysis to determine the gait alterations occurring in claudicating patients both before and after onset of claudication pain in their legs. Hip, knee, and ankle joint moments were measured in claudicating patients (age: 64.46+/-8.47 years; body mass: 80.70+/-12.64kg; body height: 1.72+/-0.08m) and were compared to gender-age-body mass-height-matched healthy controls (age 66.27+/-9.22 years; body mass: 77.89+/-10.65kg; body height: 1.74+/-0.08m). The claudicating patients were evaluated both before (pain-free (PF) condition) and after (pain condition) onset of claudication pain in their legs. Thirteen symptomatic PAD patients (26 claudicating limbs) with bilateral intermittent claudication (IC) and 11 healthy controls (22 control limbs) were tested during level walking at their self-selected speed. Compared to controls, PAD hip and ankle joints demonstrated significant angular kinematics and net internal moment changes. Alterations were present both in PF and pain conditions with several of them becoming worse in the pain condition. Both PF and pain conditions resulted in significantly reduced peak hip extensor moment (5.62+/-1.40 and 5.63+/-1.33% BWxBH, respectively) during early stance as compared to controls (7.53+/-1.16% BWxBH). In the pain condition, PAD patients had a significantly reduced ankle plantar flexor moment (7.56+/-1.41% BWxBH) during late stance as compared to controls (8.65+/-1.27% BWxBH). Furthermore, when comparing PF to pain conditions, there was a decreased peak plantar flexor moment (PF condition: 8.23+/-1.37 vs. pain condition: 7.56+/-1.41% BWxBH) during late stance. The findings point to a weakness in the posterior compartment muscles of the hip and calf as being the key factor underlying the PAD gait adaptations. Our findings establish a detailed baseline description of the changes present in PAD patient's joint angles and moments during walking. Since IC is primarily a gait disability, better understanding of the abnormalities in joint and muscle function will enhance our understanding of the gait impairment and may lead to novel, gait-specific treatments.

Virtual reality for robotic laparoscopic surgical training.

UNLABELLED: Virtual reality (VR) simulation has been used to improve training for manual laparoscopy and to give surgeons superior performance in the operating room. However, VR has not been used to train surgeons in robotic laparoscopy. SUBJECTS: Five students of the University of Nebraska Medical Center (UNMC) and the University of Nebraska at Omaha gave consent according to UNMC ethical guidelines. EXPERIMENTAL PROTOCOL: Subjects performed with the Da Vinci robotic surgical system 5 trials for each of two tasks (Bimanual Carrying, BC; Needle Passing, NP). Each task was performed first in the actual robotic operating environment and then in VR. The data analysis included time to task completion, instrument tips distance traveled and the corresponding speed, and range of motion of the elbow flexion and extension of each subject. RESULTS: The BC and NP tasks were not significantly different between the two environments with respect to robot tip speed and the elbow range of motion for both arms. Time to task completion and distance traveled were significantly different between the two environments for both tasks. Survey results showed that subjects partially agreed that it was easy to adapt to VR and felt comfortable manipulating the robot controls in VR. They also suggested that they would like to have VR as part of their regular training. Our preliminary efforts showed promise that our VR environment is valid and it can be used for training of robotic laparoscopy. However, the differences identified need to be further explored and point to the need to further improve our VR simulation.