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Biomedical subjects

Paul C LaStayo

Publications and source records attributed to Paul C LaStayo.

10 recordsLinked to original sources
PubMed2006

High-intensity resistance training amplifies muscle hypertrophy and functional gains in persons with Parkinson's disease.

Strength deficits in persons with Parkinson's disease (PD) have been identified as a contributor to bradykinesia. However, there is little research that examines the effect of resistance training on muscle size, muscle force production, and mobility in persons with PD. The purpose of this exploratory study was to examine, in persons with PD, the changes in quadriceps muscle volume, muscle force production, and mobility as a result of a 12-week high-force eccentric resistance training program and to compare the effects to a standard-care control. Nineteen individuals with idiopathic PD were recruited and consented to participate. Matched assignment for age and disease severity resulted in 10 participants in the eccentric group and 9 participants in the control group. All participants were tested prior to and following a 12-week intervention period with testing and training conducted at standardized times in their medication cycle. The eccentric group performed high-force quadriceps contractions on an eccentric ergometer 3 days a week for 12 weeks. The standard-care group exercise program encompassed standard exercise management of PD. The outcome variables were quadriceps muscle volume, muscle force, and mobility measures (6-minute walk, stair ascent/descent time). Each outcome variable was tested using separate one-way analyses of covariance on the difference scores. Muscle volume, muscle force, and functional status improvements occurred in persons with PD as a result of high-force eccentric resistance training. The eccentric group demonstrated significantly greater difference scores for muscle structure, stair descent, and 6-minute walk (P < 0.05). Magnitude of effect size estimators for the eccentric group consistently exceeded those in the standard-care group for all variables. To our knowledge, this is the first clinical trial to investigate and demonstrate the effects of eccentric resistance training on muscle hypertrophy, strength, and mobility in persons with PD. Additional research is needed to determine the anatomical and neurological mechanisms of the observed strength gains and mobility improvements.

Activities of Daily Living↗
PubMed2006

Early application of negative work via eccentric ergometry following anterior cruciate ligament reconstruction: a case report.

STUDY DESIGN: Case report. OBJECTIVES: To present a progressively increasing negative-work exercise program via eccentric ergometry early after anterior cruciate ligament reconstruction (ACL-R) and to suggest the potential of negative work to amplify the return of quadriceps size and strength. CASE DESCRIPTION: The patient was a 26-year-old highly active recreational athlete who sustained an ACL tear while skiing in January 2004 and then again while skiing in February 2005. This individual underwent an arthroscopically assisted ACL-R with a double-loop semitendinosusgracilis autograft initially, then a patellar tendon autograft following his ACL graft rupture. Beginning within 3 weeks after surgery, a progressive negative-work exercise program was initiated using an eccentric ergometer. The patient completed 31 training sessions of 5 to 30 minutes in duration over a 12-week period following the ACL-R and 33 training sessions of the same frequency and duration following the ACL revision. OUTCOMES: Following ACL-R, quadriceps volume increased 28% (involved lower extremity) and 14% (uninvolved lower extremity) during the 12-week training program. Following revision, quadriceps volume returned to similar levels at the same postoperative period as those achieved after the initial surgery (2% less on the involved side and 2% greater on the uninvolved side). Quadriceps strength, 15 weeks after ACL-R, exceeded preoperative measures by an average of 20% (involved) and 14% (uninvolved). Quadriceps strength after ACL revision exceeded all previous measures. DISCUSSION: This case report suggests that if gradually and progressively applied, negative work via eccentric ergometry can be both safe and efficacious early after ACL-R. Eccentric exercise may mitigate the prevalent muscle size and strength deficits commonly observed after ACL-R. The results of this case suggest a need for continued research with early negative work interventions following ACL-R.

Adult↗
PubMed2004

Pronator syndrome and other nerve compressions that mimic carpal tunnel syndrome.

The purpose of this clinical commentary is to provide a comprehensive review of compressive neuropathies that may mimic carpal tunnel syndrome, provide the clinician with information to differentially diagnose these median nerve compression sites, and provide an evidence-based opinion regarding conservative intervention techniques for the various compression syndromes. While rare in comparison to carpal tunnel syndrome, pronator syndrome and anterior interosseous nerve syndrome are proximal median nerve compressions that may be suspected if a patient with carpal tunnel syndrome fails to respond to conservative or surgical intervention. Differential diagnosis is based largely on the symptoms, patterns of paresthesia, and specific patterns of muscle weakness. Due to the relative rarity of pronator syndrome and anterior interosseous nerve syndrome, few controlled studies exist to determine the most effective treatment techniques. Based on sound anatomical and biomechanical considerations, anecdotal experience, and available research, however, treatment strategies for pronator syndrome and anterior interosseous nerve syndrome compression neuropathies can be divided into 4 major categories: (1) rest/immobilization, (2) modalities, (3) nerve gliding, and (4) nonconservative treatment.

Carpal Tunnel Syndrome↗
PubMed2003

The positive effects of negative work: increased muscle strength and decreased fall risk in a frail elderly population.

BACKGROUND: The objective of this study was to determine if a chronic eccentric training intervention, i.e., negative work, could limit or even reverse sarcopenia and its related impairments and functional limitations. Is high-force eccentric training tolerable by elderly people and will it result in improved muscle size, strength, balance, and fall risk? METHODS: 21 frail elderly subjects (mean age, 80 years) experienced 11 weeks of lower extremity resistance training. The experimental eccentric (ECC) group (n=11) performed negative work while exercising on a high-force eccentric ergometer. The active "controls" performed traditional (TRAD) (n=10) lower extremity resistance exercises (weight training). Muscle fiber cross-sectional area and strength, balance, stair descending abilities, and fall risk were assessed prior to and following this intervention. RESULTS: All ECC subjects who started the negative work intervention completed the study and reported the training to be relatively effortless; they experienced minimal and transient muscle soreness. Both groups experienced a significant increase in muscle fiber cross-sectional area (ECC=60%, TRAD=41%). Only the ECC group experienced significant improvements in strength (60%), balance (7%), and stair descent (21%) abilities. The timed up and go task improved in both groups, but only the ECC group went from a high to a low fall risk. CONCLUSIONS: These data demonstrate that lower extremity resistance exercise can improve muscle structure and function in those with limited exercise tolerance. The greater strength increase following negative work training resulted in improved balance, stair descent, and fall risk only in the ECC group. Because low energy cost is coupled to high force production with eccentric exercise, this intervention may be useful for a number of patients that are otherwise unable to achieve high muscle forces with traditional resistance exercise.

Accidental Falls↗
PubMed2003

Eccentric muscle contractions: their contribution to injury, prevention, rehabilitation, and sport.

Muscles operate eccentrically to either dissipate energy for decelerating the body or to store elastic recoil energy in preparation for a shortening (concentric) contraction. The muscle forces produced during this lengthening behavior can be extremely high, despite the requisite low energetic cost. Traditionally, these high-force eccentric contractions have been associated with a muscle damage response. This clinical commentary explores the ability of the muscle-tendon system to adapt to progressively increasing eccentric muscle forces and the resultant structural and functional outcomes. Damage to the muscle-tendon is not an obligatory response. Rather, the muscle can hypertrophy and a change in the spring characteristics of muscle can enhance power; the tendon also adapts so as to tolerate higher tensions. Both basic and clinical findings are discussed. Specifically, we explore the nature of the structural changes and how these adaptations may help prevent musculoskeletal injury, improve sport performance, and overcome musculoskeletal impairments.

Accidental Falls↗
PubMed2002

Do muscles function as adaptable locomotor springs?

During normal animal movements, the forces produced by the locomotor muscles may be greater than, equal to or less than the forces acting on those muscles, the consequences of which significantly affect both the maximum force produced and the energy consumed by the muscles. Lengthening (eccentric) contractions result in the greatest muscle forces at the lowest relative energetic costs. Eccentric contractions play a key role in storing elastic strain energy which, when recovered in subsequent contractions, has been shown to result in enhanced force, work or power outputs. We present data that support the concept that this ability of muscle to store and recover elastic strain energy is an adaptable property of skeletal muscle. Further, we speculate that a crucial element in that muscle spring may be the protein titin. It too seems to adapt to muscle use, and its stiffness seems to be 'tuned' to the frequency of normal muscle use.

Animals↗
PubMedDate not supplied

A supination splint worn distal to the elbow: a radiographic, electromyographic, and retrospective report.

The purposes of this study were to 1) describe a dynamic supination splint that does not cross the humeroulnar and humeroradial joints, allowing flexion and extension of the elbow; 2) provide retrospective data on effectiveness of this splint in patients with limited supination; and 3) provide data from radiography and electromyography (EMG) that document this splint's ability to provide a passive supination force. Eleven subjects treated for various elbow and/or wrist fractures leading to losses of forearm supination significantly increased their passive range of motion (PROM) from 34.0 degrees at the initial visit to 82.3 degrees at discharge and active range of motion (AROM) from 27.0 degrees to 72.3 degrees. Radiographic images of the radius and ulna were identical in maximal voluntary supination and resting in the splint. Surface EMG was used to measure supinator muscle activity at rest, passively supinated while wearing the splint, and during a maximal isometric supination effort (without splint). Average supinator EMG activity was 7.9 mV at rest, 7.8 mV in the splint, and 68.0 mV with maximal isometric contraction. Results indicate the supination splint is clinically effective in increasing supination PROM. EMG data and radiographs indicate that the splint passively positions the forearm in supination even though the proximal margin of the splint does not cross the elbow.

Adult↗
PubMedDate not supplied

Fracture healing: bone healing, fracture management, and current concepts related to the hand.

Bones fracture frequently and often result in significant impairments, functional limitations, and disabilities, especially when the hand is involved. When fractures occur, there is a disruption of the skeletal tissue organization and a loss of mechanical integrity. The goal of fracture healing is to regenerate mineralized tissue in the fracture area and restore mechanical strength to the bone. Of equal importance is the reconstitution of the normal soft tissue gliding and movement about the fracture site. This article briefly reviews the history of fracture healing and the advances in mechanics and cellular and molecular biology, which should help the reader better understand the current mechanisms related to bone healing (primarily and secondarily). Fracture fixation modes also are described along with the temporal sequencing as to when to protect or move the fractured region.

Bone and Bones↗
PubMedDate not supplied

The forearm complex: anatomy, biomechanics and clinical considerations.

The forearm complex is comprised of the proximal radioulnar joint, middle radioulnar joint/interosseous membrane, and the distal radioulnar joint. These three areas function in a coordinated manner to rotate the hand in space and allow performance of functional tasks. If a structure or structures in one of these three areas is disrupted, this can adversely affect the function at any of the other two remaining areas. Surgical intervention focuses on restoring anatomical alignment to preserve the function of the forearm complex. Rehabilitation is guided by the relationships between the three areas of the forearm complex and the awareness of clinical signs, symptoms, and complications. The purposes of this paper are to 1) describe the anatomy and biomechanical function of the forearm complex and 2) discuss clinical correlates pertaining to select forearm injuries (excluding peripheral nerve injuries) that may affect forearm function.

Biomechanical Phenomena↗