Robin L. Marcus

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

Strength deficits in persons with Parkinsons 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.

High intensity eccentric resistance training decreases bradykinesia and improves Quality Of Life in persons with Parkinson's disease: a preliminary study.

Persons with Parkinson disease (PD) often demonstrate bradykinesia during mobility tasks. Bradykinesia combined with other PD-related movement deficits may contribute to self-reported reductions in quality of life. At this time, no studies have examined the effects of resistance exercise as an intervention to reduce bradykinesia and improve self-reported quality of life. Therefore, we examined changes in muscle force production, clinical measures of bradykinesia, and quality of life following 12 weeks of a high intensity eccentric resistance exercise program in persons with mild to moderate PD. Twenty individuals with idiopathic PD were matched into an experimental or an active control group. All participants were tested prior to and following a 12-week intervention period. The experimental group performed high intensity quadriceps contractions on an eccentric ergometer 3 days a week for 12 weeks. The active control group participated in an evidence based exercise program of PD. The outcome variables were quadriceps muscle force, clinical bradykinesia measures (gait speed, timed up and go) and disease specific quality of life (Parkinsons disease questionnaire-39 [PDQ-39]). Data was analyzed using separate 2 (group) x 2 (time period) ANOVAs. Results demonstrated significant time by group interaction effects for gait speed, timed up and go, and the composite PDQ-39 score (p < 0.05). Muscle force, bradykinesia, and QOL were improved to a greater degree in those that performed high intensity eccentric resistance training compared to an active control group. Additional research is needed to determine if this type of training has long-term impact and if it results in an alteration of the natural history of mobility and QOL decline in persons with PD.

Total Knee Arthroplasty: Muscle Impairments, Functional Limitations, and Recommended Rehabilitation Approaches

UNLABELLED The number of total knee arthroplasty (TKA) surgeries performed each year is predicted to steadily increase. Following TKA surgery, self-reported pain and function improve, though individuals are often plagued with quadriceps muscle impairments and functional limitations. Postoperative rehabilitation approaches either are not incorporated or incompletely address the muscular and functional deficits that persist following surgery. While the reason for quadriceps weakness is not well understood in this patient population, it has been suggested that a combination of muscle atrophy and neuromuscular activation deficits contribute to residual strength impairments. Failure to adequately address the chronic muscle impairments has the potential to limit the long-term functional gains that may be possible following TKA. Postoperative rehabilitation addressing quadriceps strength should mitigate these impairments and ultimately result in improved functional outcomes. The purpose of this paper is to describe these quadriceps muscle impairments and discuss how these impairments can contribute to the related functional limitations following TKA. We will also describe the current concepts in TKA rehabilitation and provide recommendations and clinical guidelines based on the current available evidence. LEVEL OF EVIDENCE Therapy, level 5.

Comparison of anterior cruciate ligament reconstructions using patellar tendon autograft or allograft

Seventy-eight of 113 consecutive patellar tendon anterior cruciate ligament reconstructions (autograft, 47 of 66; allograft, 31 of 47) were evaluated at an average of 34 months. Reconstructions were compared with Lysholm and Tegner knee-rating scales, physical examination findings, instrumented laxity values, single-leg hop distances, and isokinetic strength results. Lysholm scores > or = 90 were achieved by 69% of autograft patients versus 67% of allograft patients. Desired Tegner activity scores were achieved by 80% of autograft patients versus 74% of allograft patients. Patellofemoral signs and symptoms were absent in 40% of autograft patients versus 44% of allograft patients. Side-to-side laxity differences < or = 3 mm were achieved in 80% of autograft patients versus 70% of allograft patients. Single-leg hop scores > or = 90% of the nonoperated leg were obtained in 76% of autograft patients versus 81% of allograft patients. Isokinetic results between groups were also similar. Traumatic ruptures were sustained by four allograft patients at an average of 11 months postoperatively compared with no traumatic ruptures in the autograft group (P = .011). This was the only difference of statistical significance.

Intermuscular Fat: A Review of the Consequences and Causes

Muscles structural composition is an important factor underlying muscle strength and physical function in older adults. There is an increasing amount of research to support the clear disassociation between the loss of muscle lean tissue mass and strength with aging. This disassociation implies that factors in addition to lean muscle mass are responsible for the decreases in strength and function seen with aging. Intermuscular adipose tissue (IMAT) is a significant predictor of both muscle function and mobility function in older adults and across a wide variety of comorbid conditions such as stroke, spinal cord injury, diabetes, and COPD. IMAT is also implicated in metabolic dysfunction such as insulin resistance. The purpose of this narrative review is to provide a review of the implications of increased IMAT levels in metabolic, muscle, and mobility function. Potential treatment options to mitigate increasing levels of IMAT will also be discussed.

Sensory cueing effects on maximal speed gait initiation in persons with Parkinson's disease and healthy elders

Researchers have suggested that sensory cues can improve gait initiation in persons with Parkinsons disease (PD); however, there is little research that documents the effects of sensory cues on gait initiation. The purpose of this study was to examine the effects of auditory and cutaneous sensory cues on maximal speed gait initiation in persons with PD and healthy elderly. Seven persons with PD of moderate severity (mean age=69 years) and seven age, gender, and height matched healthy elders participated. Temporal, kinematic and center of pressure (COP) data were recorded as participants performed eight trials within four randomly ordered conditions (no cue (NC), a single auditory cue (SA), repetitive auditory cues (RA), and repetitive cutaneous cues (RC)). In each condition, participants were instructed to perform each gait initiation trial at their maximal speed. In all conditions, persons with PD reacted more slowly and moved less far than did the matched elders. Relative to conditions with NCs, sensory cueing resulted in decreased double limb support (DLS), and increased COP displacement and velocity in both groups. However, in both groups, displacements and velocities of the swing limb and sacrum during the sensory-cued conditions were less than those during the NC condition. These results suggest that when movement speed is a primary goal, sensory cues may interfere with swing limb and body movement outcomes during the gait initiation task in both persons with PD and healthy elders.

Intramuscular adipose tissue, sarcopenia, and mobility function in older individuals.

Objective. Intramuscular adipose tissue (IMAT) and sarcopenia may adversely impact mobility function and physical activity. This study determined the association of locomotor muscle structure and function with mobility function in older adults. Method. 109 older adults with a variety of comorbid disease conditions were examined for thigh muscle composition via MRI, knee extensor strength via isometric dynamometry, and mobility function. The contribution of strength, quadriceps lean tissue, and IMAT to explaining the variability in mobility function was examined using multivariate linear regression models. Results. The predictors as a group contributed 27–45% of the variance in all outcome measures; however, IMAT contributed between 8–15% of the variance in all four mobility variables, while lean explained only 5% variance in only one mobility measure. Conclusions. Thigh IMAT, a newly identified muscle impairment appears to be a potent muscle variable related to the ability of older adults to move about in their community.

A Prospective Evaluation of Untreated Acute Grade III Acromioclavicular Separations

We prospectively studied the natural history of untreated acute grade III acromioclavicular separations. Twenty-five patients were treated nonoperatively with a sling for comfort through progressive early range of motion as tolerated. Ten additional uninjured subjects underwent strength testing to evaluate the difference between the dominant and nondominant sides so that patient data could be standardized. The patients were examined at intervals of 6, 12, 24, 36, and 52 weeks after injury, at which time they completed a subjective questionnaire and underwent isometric dynamometer testing as well as military press and bench press strength testing. One patient underwent a surgical procedure at 2 weeks after injury because of cosmetic concerns. Twenty of the 25 patients completed the 1-year evaluation and strength-testing protocol. Subjectively, 4 of the 20 patients (20%) thought that their long-term outcome was suboptimal, although for 3 of them it was not enough to warrant surgery. Objective examination and strength testing of the 20 patients revealed no limitation of shoulder motion in the injured extremity and no difference between sides in rotational shoulder muscle strength. The bench press was the only strength test that showed a significant short-term difference, with the injured extremity being an average of 17% weaker. This study documents the natural history of patients with an untreated acute grade III acromioclavicular separation and provides a reference with which to judge all other proposed methods of treatment.

Total knee arthroplasty

UNLABELLED The number of total knee arthroplasty (TKA) surgeries performed each year is predicted to steadily increase. Following TKA surgery, self-reported pain and function improve, though individuals are often plagued with quadriceps muscle impairments and functional limitations. Postoperative rehabilitation approaches either are not incorporated or incompletely address the muscular and functional deficits that persist following surgery. While the reason for quadriceps weakness is not well understood in this patient population, it has been suggested that a combination of muscle atrophy and neuromuscular activation deficits contribute to residual strength impairments. Failure to adequately address the chronic muscle impairments has the potential to limit the long-term functional gains that may be possible following TKA. Postoperative rehabilitation addressing quadriceps strength should mitigate these impairments and ultimately result in improved functional outcomes. The purpose of this paper is to describe these quadriceps muscle impairments and discuss how these impairments can contribute to the related functional limitations following TKA. We will also describe the current concepts in TKA rehabilitation and provide recommendations and clinical guidelines based on the current available evidence. LEVEL OF EVIDENCE Therapy, level 5.

Effects of Early Progressive Eccentric Exercise on Muscle Size and Function After Anterior Cruciate Ligament Reconstruction: A 1-Year Follow-up Study of a Randomized Clinical Trial

Background and Purpose: The authors previously reported that focused eccentric resistance training during the first 15 weeks following anterior cruciate ligament reconstruction (ACL-R) induced greater short-term increases in muscle volume, strength, and measures of function relative to standard rehabilitation. The purpose of this study was to evaluate the effects of early progressive eccentric exercise on muscle volume and function at 1 year after ACL-R. Participants and Methods: Forty patients who had undergone an ACL-R were randomly assigned to 1 of 2 groups: a group that received early progressive eccentric exercise (n=20) and a group that received standard rehabilitation (n=20). Seventeen participants in the eccentric exercise group and 15 participants in the standard rehabilitation group completed a 1-year follow-up. Magnetic resonance images of the thighs were acquired 1 year after ACL-R and compared with images acquired 3 weeks after surgery. Likewise, routine knee examinations, self-report assessments, and strength and functional testing were completed 1 year after surgery and compared with previous evaluations. A 2-factor analysis of variance for repeated measures (group × time) was used to analyze the data. Results: Compared with the standard rehabilitation group, improvements in quadriceps femoris and gluteus maximus muscle volume in the involved lower extremity from 3 weeks to 1 year following ACL-R were significantly greater in the eccentric exercise group. Improvements in quadriceps femoris and gluteus maximus muscle volume were 23.3% (SD=14.1%) and 20.6% (SD=12.9%), respectively, in the eccentric exercise group and 13.4% (SD=10.3%) and 11.6% (SD=10.4%), respectively, in the standard rehabilitation group. Improvements in quadriceps femoris muscle strength and hopping distance also were significantly greater in the eccentric exercise group 1 year postsurgery. Discussion and Conclusions: A 12-week focused eccentric resistance training program, implemented 3 weeks after ACL-R, resulted in greater increases in quadriceps femoris and gluteus maximus muscle volume and function compared with standard rehabilitation at 1 year following ACL-R.