The relation between kinematic synergy to stabilize the center of mass during walking and future fall risks: a 1-year longitudinal study.

Background: Incorrect body weight shifting is a frequent cause of falls, and the control of the whole-body center of mass (CoM) by segmental coordination is essential during walking. Uncontrolled manifold (UCM) analysis is a method of examining the relation between variance in segmental coordination and CoM stability. However, no prospective cohort study has thoroughly investigated how variance in segmental configurations to stabilize the CoM relates to future falls.

Relation between frontal plane center of mass position stability and foot elevation during obstacle crossing.

High foot elevation during obstacle crossing is viewed as a conservative strategy in older adults, but excessive foot elevation may result in large mediolateral center of mass (CoM) displacement. Since an incorrect transfer of CoM can lead to balance loss during locomotion, both appropriate foot elevation and CoM position must be controlled and coordinated by adjusting body segment positions. However, no studies have revealed time profiles of CoM position by coordinated segment movements and the relation of foot elevation with CoM position during obstacle crossing.

Contributions of Muscle Elasticity and Lateral Slide of the Transversus Abdominis to Lumbar Stability.

Context: Lumbar instability can cause lumbar spondylolisthesis and chronic low-back pain in sports situation. Abdominal hollowing is commonly used in clinical practice to preferentially target the transversus abdominis (TrA) to stabilize the lumbar vertebrae; however, the contribution of muscle elasticity and lateral slide of the TrA to lumbar stability has not yet been clarified.

Objective: To clarify the contribution of elasticity and lateral slide of the TrA to lumbar stability and to identify an effective exercise to stabilize the lumbar vertebrae.

Injuries associated with Japanese high-school men's volleyball: a two-year survey and analysis.

[Purpose] There are many factors associated with sports injuries in volleyball that remain unclear; therefore, many of these injuries are still not being effectively prevented. This study aimed to help effectively prevent injuries among and provide conditioning guidance to participants of a high-school men's volleyball team. [Participants and Methods] The participants were 36 males of a high-school men's volleyball team, and the circumstances of injury occurrence, injury type, injury site, exposure time, and injury rate per 1,000 player-hours were evaluated among these participants.

The relation between limb segment coordination during walking and fall history in community-dwelling older adults.

Control of the swing foot during walking is important to prevent falls. The trajectories of the swing foot are adjusted by coordination of the lower limbs, which is evaluated with uncontrolled manifold (UCM) analysis. A previous study that applied this analysis to walking revealed that older adults with fall history had compensatorily great segment coordination to stabilize the swing foot during normal walking.

Abdominal girth as an index of muscle tension during abdominal hollowing: Selecting the optimal training intensity for the transversus abdominis muscle.

The abdominal hollowing technique is used for training the transversus abdominis (TrA). However, the optimal intensity of hollowing is still unclear. The objective of the present study is to verify the validity of estimating the tension of the TrA by measuring the girth of the abdomen with a tape and to determine the optimum intensity of hollowing to effectively train the TrA.

Effect of different knee flexion angles with a constant hip and knee torque on the muscle forces and neuromuscular activities of hamstrings and gluteus maximus muscles.

Purpose: This study examined the effect of different knee flexion angles with a constant hip and knee torque on the muscle force and neuromuscular activity of the hamstrings and gluteus maximus.

Methods: Twenty healthy males lay in prone position and held their lower limb with hip flexion at 45° and knee flexion at either 10° or 80°. At these angles, the hip and knee torques are identical.

The effects of fall history on kinematic synergy during walking.

To prevent falls, control of the swing foot during walking is crucial. Recently, some studies demonstrated that the coordinated movement of lower limbs by kinematic synergy is important for stable walking. However, no study has been carried out to reveal the relation between falls and kinematic synergy, and it is unclear whether fall history alters the kinematic synergy.

Scapular kinematic and shoulder muscle activity alterations after serratus anterior muscle fatigue.

Background: Although the serratus anterior muscle has an important role in scapular movement, no study to date has investigated the effect of serratus anterior fatigue on scapular kinematics and shoulder muscle activity. The purpose of this study was to clarify the effect of serratus anterior fatigue on scapular movement and shoulder muscle activity.

Methods: The study participants were 16 healthy men.