Ming-Wei Liu

Patients with type II diabetes mellitus display reduced toe-obstacle clearance with altered gait patterns during obstacle-crossing

Patients with type II diabetes mellitus (DM) have been reported to be at high risk of falls that may be further increased by the effects of challenging activities such as obstacle-crossing. The purpose of this study was to compare the end-point trajectory and joint kinematic and kinetic patterns of the lower extremities between healthy subjects and individuals with DM during obstacle-crossing with the leading limb. Fourteen patients with type II DM, with no to minimal peripheral neuropathy (PN), and 14 healthy controls walked and crossed obstacles of three different heights (10%, 20% and 30% of leg length) while kinematic and kinetic data were measured using a motion analysis system and two forceplates. Compared to normal, the DM group had similar walking speeds and horizontal footobstacle distances but significantly reduced leading toe-obstacle clearances, suggesting an increased risk of tripping over the obstacle. When the swing toe was above the obstacle, the DM group showed greater pelvic anterior tilt, stance ankle dorsiflexion, and smaller swing hip abduction, with reduced hip abductor moments but greater knee flexor and ankle plantarflexor and adductor moments. It is suggested that patients with type II DM, with no or minimal PN, should also be targeted for prevention of falls. Possible therapeutic interventions to decrease falls for those with DM may include strengthening of the knee flexors and ankle plantarflexor muscles, together with proprioception and balance training.

Control of the motion of the body's center of mass in relation to the center of pressure during high-heeled gait.

High-heeled shoes are associated with instability and falling, leading to injuries such as fracture and ankle sprain. Knowledge of the motion of the bodys center of mass (COM) with respect to the center of pressure (COP) during high-heeled gait may offer insights into the balance control strategies and provide a basis for approaches that minimize the risk of falling and associated adverse effects. The study aimed to investigate the influence of the base and height of the heels on the COM motion in terms of COM-COP inclination angles (IA) and the rate of change of IA (RCIA). Fifteen females who regularly wear high heels walked barefoot and with narrow-heeled shoes with three heel heights (3.9cm, 6.3cm and 7.3cm) while kinematic and ground reaction force data were measured and used to calculate the COM and COP, as well as the temporal-distance parameters. The reduced base of the heels was found to be the primary factor for the reduced normalized walking speed and the reduced frontal IA throughout the gait cycle. This was achieved mainly through the control of the RCIA during double-leg stance (DLS). The heel heights affected mainly the peak RCIA during DLS, which were not big enough to affect the IA. These results suggest young adults adopt a conservative strategy for balance control during narrow-heeled gait. The results will serve as baseline data for future evaluation of patients and/or older adults during narrow-heeled gait with the aim of reducing the risk of falling.

Control of Body's Center of Mass Motion During Level Walking and Obstacle-Crossing in Older Patients with Knee Osteoarthritis

Knee osteoarthritis (OA) has been reported to affect the performance of ambulation, including unobstructed and obstructed gait. An increased risk of falling in patients with knee OA during obstaclecrossing, as opposed to unobstructed level walking, may be explained by the difference in the control of the bodys center of mass (COM) with respect to the center of pressure (COP) while trying to ensure sufficient foot clearance. The purpose of the study was to investigate the dynamic stability in patients with knee OA during level walking and obstacle-crossing. The COM-COP inclination angles and angular velocities, as well as temporal-spatial variables, from eleven patients with bilateral knee OA and eleven normal controls were obtained during level walking and obstacle-crossing using a three-dimensional motion analysis system and forceplates. Demands in the control of the COM relative to the COP were found to be greater during obstacle-crossing in both subject groups. While less stable COM control was found around the end stage of double stance phase during obstacle-crossing when compared to level walking, patients with knee OA successfully acquired strategies in the sagittal plane to maintain close-tonormal stable COM control with normal toe clearances during both level walking and obstacle-crossing. They achieved stable transitions from single limb stance (SLS) to double limb stance (DLS) through a reduced anterior inclination angle and from DLS to SLS through increased anterior angular velocity. It is suggested that assessment of the ability to control dynamic stability in patients with knee OA should consider both the positions and velocities of the COM and COP.

Effects of long-term wearing of high-heeled shoes on the control of the body's center of mass motion in relation to the center of pressure during walking

High-heeled shoes are associated with instability and falling, leading to injuries such as fracture and ankle sprain. This study investigated the effects of habitual wearing of high-heeled shoes on the bodys center of mass (COM) motion relative to the center of pressure (COP) during gait. Fifteen female experienced wearers and 15 matched controls walked with high-heeled shoes (7.3cm) while kinematic and ground reaction force data were measured and used to calculate temporal-distance parameters, joint moments, COM-COP inclination angles (IA) and the rate of IA changes (RCIA). Compared with inexperienced wearers, experienced subjects showed significantly reduced frontal IA with increased ankle pronator moments during single-limb support (p<0.05). During double-limb support (DLS), they showed significantly increased magnitudes of the frontal RCIA at toe-off and contralateral heel-strike, and reduced DLS time (p<0.05) but unaltered mean RCIA over DLS. In the sagittal plane experienced wearers showed significantly increased mean RCIA (p<0.05) and significant differences in the RCIA at toe-off and contralateral heel-strike (p<0.05). Significantly increased hip flexor moments and knee extensor moments at toe-off (p<0.05) were needed for forward motion of the trailing limb. The current results identified the change in the balance control in females after long-term use of high-heeled shoes, providing a basis for future design of strategies to minimize the risk of falling during high-heeled gait.

Inter-joint sharing of total support moments in the lower extremities during gait in narrow-heeled shoes of different heights

The study aimed to investigate the influence of the base and height of shoe heels on the total support moment (Ms) and individual joint contributions during gait. Fifteen healthy females walked barefoot and with narrow-heeled shoes (heel heights: 3.9, 6.3 and 7.3 cm) while kinematic and kinetic data were measured. Compared with the barefoot condition, the subjects maintained unaltered Ms in the sagittal plane in shod conditions. This was achieved by increasing the knee extensor moment to compensate for the diminished ankle plantarflexor moments in medium and high heel conditions. In the frontal plane, subjects in shod conditions had to sustain an increased Ms for balance control during late single-leg stance with increased knee abductor and ankle pronator moments as a result of the reduced base of the heels. The results will be helpful for future shoe designs to reduce fall risks and prevent relevant musculoskeletal problems Practitioner Summary: Knowledge of the influence of narrow-heeled shoes on lower limb support moments helps in shoe design to address fall risks. Gait analysis showed that females in narrow-heeled shoes maintained unaltered sagittal total support moments but sustained an increased demand in the frontal plane during late single-leg stance.

KINEMATIC AND KINETIC ADAPTATIONS IN THE LOWER EXTREMITIES OF EXPERIENCED WEARERS DURING HIGH-HEELED GAIT

High-heeled shoes are associated with falling, leading to injuries such as fracture and ankle sprain. The study aimed to investigate the kinematic and kinetic adaptations in the lower extremities resulting from habitual use of high-heeled shoes. A total of 15 female experienced wearers and 15 matched controls walked with high-heeled shoes (7.3 cm) while kinematic and ground reaction force data were measured and used to calculate the joint angles and moments, as well as the temporal-distance parameters. Compared with inexperienced wearers, experienced wearers appeared to adopt a specific control strategy to improve the stability of the support ankle and knee while preventing excessive loading at the knee and hip. Increased hip abduction during early stance phase and increased pelvis rotation toward the ipsilateral side at contralateral heel-strike appeared to contribute toward the reduced step width for a better adjustment of the medio-lateral motion of the bodys center of mass in order to maintain stability. At the hip, increased abductor moments may help to increase the pelvis stability and prevent excessive loading at the knee, and reduced internal rotator moments may reduce the torsional loading at the hip. At the knee, reduced ranges of flexion-extension and adduction-abduction motions may increase its stability. At the ankle, increased external rotation angles, together with increased pronator and external rotator moments through increased ground reaction force, may enhance the ankle stability. The current results identified the changes in the kinematics and kinetics of the lower extremities in females after long-term use of high-heeled shoes, providing a basis for future development of training programs and design of new high-heeled shoes to help those who have higher risks of falling and injuries during high-heeled gait.

LOWER LIMB JOINT POSITION SENSE IN PATIENTS WITH TYPE II DIABETES MELLITUS

Diabetes mellitus (DM), of which type II has been described as an international epidemic, is a major cause of death. Diabetic peripheral neuropathy (PN) is a condition secondary to hyperglycemia, where progressive loss of peripheral nerve function, including sensory and motor functions, occurs over time. Early detection of PN-related impairments may be helpful for the management of patients with DM. Among the methods for the evaluation of these impairments, only that for joint position sense (JPS) requires both motor and sensory involvement. The purpose of the current study was to compare the JPS of the lower limb joints in patients with no or mild diabetic PN to those of normal controls both during weight-bearing (WB) and non-weight-bearing (NWB) conditions using 3D motion analysis methods. The results supported the hypothesis that in well controlled diabetic patients with no or mild PN, JPS deficits can be found only at the ankle joint during WB conditions, resulting in overestimation of dorsiflexion angles. This suggests that at the very early stage of development of diabetic PN, distal joint involvement precedes that of proximal joints. Early detection of these changes, through the assessment of the JPS for all the lower limb joints under both NWB and WB conditions, will be helpful for the development of clinical preventive and treatment programs for patients with DM, even if their glucose level are well controlled. Gait and balance training in these patients should emphasize proprioception training exercises during WB conditions.

Biomechanical risk factors for tripping during obstacle--Crossing with the trailing limb in patients with type II diabetes mellitus.

People with type II diabetes mellitus (DM) are at a high risk of falling especially during more challenging locomotor tasks such as obstacle-crossing. The current study aimed to identify the risk factors for tripping in these patients during trailing-limb obstacle-crossing. Fourteen patients with type II DM with or without mild peripheral neuropathy (PN) and 14 healthy controls walked and crossed obstacles of three different heights while their motion data were measured using a motion capture system and two forceplates. The DM group was found to cross obstacles with significantly reduced trailing toe clearance (p<0.05), increasing the probability of the foot hitting the obstacle, and thus the risk of tripping. This altered end-point control was associated with significantly reduced knee flexion and hip adduction of the trailing swing limb (p<0.05), as well as significantly increased ankle plantarflexor moments in the leading stance limb (p<0.05). Therefore, reduced knee flexion and hip adduction of the swing limb are identified as risk factors for tripping during obstacle-crossing. Increased mechanical demands on the ankle plantarflexors suggest that weakness of these muscles may further reduce the already compromised performance of obstacle-crossing in these patients. The current results showed that obstacle-crossing can be used to detect gait deviations and to identify the associated risk of tripping in patients with type II DM without or at an early stage of PN.