Effects of Neuromuscular Electrical Stimulation Waveforms and Occlusion Pressures on Elicited Force and Microvascular Oxygenation.

Context: Interest in the effects of concurrently using neuromuscular electrical stimulation (NMES) and blood flow restriction (BFR) to improve muscle strength has risen, but limited studies and inconsistent findings have led to more questions. The 2 current projects aimed to systematically investigate how NMES waveform shape and BFR occlusion pressure acutely influence electrically elicited force (EEF) and tissue oxygen saturation (StO2) of the knee extensors.

Design: A single-session repeated-measures design was followed.

Acute Effects of 3 Neuromuscular Electrical Stimulation Waveforms on Exercising and Recovery Microvascular Oxygenation Responses.

Context: When emphasizing muscular strength during postoperative rehabilitation it is recommended to use a neuromuscular electrical stimulation (NMES) waveform that elicits the greatest muscle force and local metabolic demand that is also well tolerated. The present investigation examined the effects that 3 different clinically used NMES waveforms had on the electrically elicited force (EEF), local metabolic demand (exercising muscle oxygen saturation [SmO2]), and the subsequent reactive hyperemia response (recovery total hemoglobin concentration [THb]) of the knee extensors.

Design: Single session repeated-measures design.

Changes in microvascular oxygenation and total hemoglobin concentration of the vastus lateralis during neuromuscular electrical stimulation (NMES).

: Neuromuscular electrical stimulation (NMES) is predicated on eliciting muscle contractions and increasing muscle demand to promote increase in strength. Previous studies have shown differences in the magnitude of elicited force among various NMES waveforms but less is known about metabolic demand of muscle during NMES.: The purpose of this study was to compare elicited force and muscle metabolic demand during electrically elicited contractions using different NMES waveforms.

Efficiency of neuromuscular electrical stimulation: A comparison of elicited force and subject tolerance using three electrical waveforms.

Objective: Efficacy of neuromuscular electrical stimulation (NMES) is limited by the discomfort of electrically elicited contractions. Most studies of tolerance to NMES have examined stimulation to maximal tolerance. NMES efficiency is the amount of elicited force at a specific level of tolerance.

Muscle force production with low and medium frequency burst modulated biphasic pulsed currents.

Objective: Russian current, a medium frequency burst modulated alternating current (BMAC), is widely used for NMES, but has not been shown to elicit forces near voluntary maximum. In contrast, low frequency BMAC has been shown to produce greater force production than Russian and most recently, medium frequency burst modulated biphasic pulsed current (BMBPC) elicited greater force than Russian. Whether low frequency BMBPC yields greater force than medium frequency BMBPC is unknown.

Interferential and burst-modulated biphasic pulsed currents yield greater muscular force than Russian current.

Objective: Previous data regarding neuromuscular electrical stimulation (NMES) have suggested that muscle torque production with interferential current (IFC) is inferior to Russian current; however, waveform parameters specific and critical to NMES were inconsistent, making interpretation of previous findings precarious. The purpose of this investigation was to compare muscle force production of three electrical stimulating waveforms when using equivalent stimulus parameters.

Design: The percent of maximal voluntary isometric knee extensor force (%MVIF) elicited using interferential, Russian, and burst-modulated biphasic pulsed currents were compared in 23 healthy college-aged subjects.

Facilitating activation of the peroneus longus: electromyographic analysis of exercises consistent with biomechanical function.

Exercises for the ankle are often used to improve sport performance through balance and stability or to prevent or recover from ankle injury. Ankle training programs often include exercises for the primary muscle of the lateral ankle, the peroneus longus (PL). However, many exercises for the PL are non-weight bearing and unidirectional.

Effect of acute fatigue of the hip abductors on control of balance in young and older women.

Objective: To examine the effects of acute fatigue of the hip abductors on the control of balance in young and older women.

Design: Pretest-posttest.

Setting: University research laboratory.

Control of balance differs after knee or ankle fatigue in older women.

Objective: To examine the effects of acute isokinetic knee or ankle fatigue on control of static and dynamic balance in older women.

Design: Pretest and posttest.

Setting: University research laboratory.

A comparison of bone mineral density in adolescent female swimmers, soccer players, and weight lifters.

Purpose: The study was designed to examine the effect of sports of varying skeletal loading on bone density in adolescent female athletes.

Methods: Bone mineral densities of female swimmers, soccer players, and weight lifters were examined. Between-sport comparisons were made using a one-way analysis of covariance with age and body mass index as covariates and group bone mass density (BMD) was compared to the World Health Organization's (WHO) normative values for adult females.

Effects of a short-term dynamic balance training program in healthy older women.

Purpose: Aging is associated with deterioration of the physiologic systems controlling balance. Consequently, a multitude of intervention trials has appeared in the last 2 decades attempting to improve control of balance. Effective programs often require substantial and frequent time commitments, expensive and specialized equipment, professional assistance, and clinical settings.

A comparison of 3 hand-held dynamometers used to measure hip abduction strength.

Quantification of strength with hand-held dynamometers is commonplace. Hand-held dynamometers offer ease of use; however, previous investigations have shown much variability between repeated measures using the same dynamometer. Even less is known regarding the degree of variability between various dynamometers.

The initial effects of low-volume strength training on balance in untrained older men and women.

Evidence indicates that leg weakness in older adults is associated with decreased control of balance. The gender-specific implications of strength training on control of balance in older men and women remains unknown. This study examined the initial adaptations to 12 weeks of low-volume, single-set-to-failure strength training and its effect on quadriceps strength and control of multidirectional balance in previously untrained older men (n = 11) and women (n = 11) 59-83 years of age.