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Biomedical subjects

Jennifer A Hess

Publications and source records attributed to Jennifer A Hess.

5 recordsLinked to original sources
PubMed2006

Ankle force and rate of force production increase following high intensity strength training in frail older adults.

BACKGROUND AND AIMS: The most common cause of accidental injury and death in people over age 65 results from impacts associated with falling. Balance impaired older adults have poorer balance control than healthy young adults or healthy older adults. Lack of sufficient lower extremity strength and inability to rapidly produce muscle force may contribute to diminished balance control in the elderly. This study evaluated the effect of a 10-week high intensity strength-training program targeting key lower extremity muscles for the purpose of improving postural control in frail older adults. METHODS: Thirteen experimental and fourteen control subjects, all balance impaired older adults were evaluated in response to unexpected platform perturbations that simulated slips. RESULTS: Following strength training the experimental group was significantly stronger than the control group. Mean ankle moments improved in the experimental group following strength training during forward sway (Right: p=0.067, Left: p=0.009) and backward sway (Right: p=0.031, Left: p=0.058). For the backward sway condition the ankle rate of torque production increased significantly in the experimental group (Right: p=0.016, Left: p=0.031). CONCLUSIONS: Enhancement of lower extremity strength contributed to improvements in balance stability demonstrated by greater ankle force production, in response to balance threats.

Accidental Falls↗
PubMed2005

Effect of high-intensity strength-training on functional measures of balance ability in balance-impaired older adults.

OBJECTIVE: The aim of this study was to evaluate the effect of a 10-week, high-intensity strength-training program targeting key lower extremity muscles for the purpose of improving postural control in balance-impaired older adults. METHODS: A quasi-experimental, delayed entry controlled design was used to evaluate balance ability in balance-impaired older adults after participation in 10 weeks of high-intensity strength training focused on the quadriceps, hamstrings, tibialis anterior, and gastrocnemius muscles. Participants were evaluated using validated clinical measures of functional balance ability: the Berg Balance Scale, the Timed Up and Go, and the Activities-Specific Balance Confidence Scale. RESULTS: After strength training, the exercisers were significantly stronger than the control subjects. They improved significantly on the Berg Balance Scale (P = .030) from a mean score of 48.8 +/- 2.4 of 56 before training to 51.2 +/- 4.3 of 56 after training. The Timed Up and Go (P = .045) and the Activities-Specific Balance Confidence Scale (P = .038) also improved significantly in the experimental group. These changes are associated with a decrease in fall risk. CONCLUSIONS: High-intensity strength training can safely and effectively strengthen lower extremity muscles in balance-impaired older adults, resulting in significant improvements in functional balance ability and decreased fall risk.

Aged↗
PubMed2004

A participatory ergonomics intervention to reduce risk factors for low-back disorders in concrete laborers.

Construction laborers rank high among occupational groups with work-related musculoskeletal injuries involving time way from work. The goals of this project were to: (1) introduce an ergonomic innovation to decrease the risk of low-back disorder (LBD) group membership, (2) quantitatively assess exposure, and (3) apply a participatory intervention approach in construction. Laborers manually moving a hose delivering concrete to a placement site were evaluated. The hypothesis tested was that skid plates would prevent hose joints from catching on rebar matting, and the hose would slide more easily. This would decrease the need for repetitive bending and use of excessive force. Four laborers were evaluated wearing the Lumbar Motion Monitor (LMM), a tri-axial electrogoniometer that records position, velocity and acceleration. Workers were measured during three comparable concrete pours. Worker perceptions of the innovation utility and exertion were surveyed. During initial use of skid plates, flexion increased significantly (p < 0.001) while velocity, acceleration and moments did not change. After implementing a worker modification, low back velocity, acceleration and moments were significantly reduced (p < 0.05). Reductions in these factors have been associated with decreased risk of belonging to an occupational group with LBDs. Use of secured skid plates during horizontal concrete hose movement may in part decrease the risk of LBD group membership among concrete laborers. Crew participation resulted in skid plates being a more effective intervention. The LMM is a promising tool for quantitative assessment in construction.

Adult↗