The effects of open and closed kinetic chain exercises on the static and dynamic balance of the ankle joints in young healthy women

A versatile knee exoskeleton mitigates quadriceps fatigue in lifting, lowering, and carrying tasks

The quadriceps are particularly susceptible to fatigue during repetitive lifting, lowering, and carrying (LLC), affecting worker performance, posture, and ultimately lower-back injury risk. Although robotic exoskeletons have been developed and optimized for specific use cases like lifting-lowering, their controllers lack the versatility or customizability to target critical muscles across many fatiguing tasks. Here, we present a task-adaptive knee exoskeleton controller that automatically modulates virtual springs, dampers, and gravity and inertia compensation to assist squatting, level walking, and ramp and stairs ascent/descent. Unlike end-to-end neural networks, the controller is composed of predictable, bounded components with interpretable parameters that are amenable to data-driven optimization for biomimetic assistance and subsequent application-specific tuning, for example, maximizing quadriceps assistance over multiterrain LLC. When deployed on a backdrivable knee exoskeleton, the assistance torques holistically reduced quadriceps effort across multiterrain LLC tasks (significantly except for level walking) in 10 human users without user-specific calibration. The exoskeleton also significantly improved fatigue-induced deficits in time-based performance and posture during repetitive lifting-lowering. Last, the system facilitated seamless task transitions and garnered a high effectiveness rating postfatigue over a multiterrain circuit. These findings indicate that this versatile control framework can target critical muscles across multiple tasks, specifically mitigating quadriceps fatigue and its deleterious effects.

Adding Weight Shift Training to Weight Reduction Decreases the Risk of Falling in Obese Women: A Prospective Randomized Controlled Trial

OBJECTIVE

The aim of this study was to examine the effect of adding weight shift training to a weight loss program on the risk of falling, fear of falling, overall stability, anteroposterior stability, mediolateral stability, and isometric knee torque in young obese women.

DESIGN

A single-blinded, randomized controlled study was performed. Sixty women, 18 to 46 yrs old, were randomly assigned either to the study or the control group. The participants in the study group were given weight-shifting training plus a weight reduction program; the control group received only a weight-reduction program. The interventions were performed for 12 wks. At baseline and after 12 wks of training, the risk of falling, fear of falling, overall stability, anteroposterior stability, mediolateral stability, and isometric knee torque were all examined.

RESULTS

There were statistically significant differences in risk of falling, fear of falling, isometric knee torque, and overall, anteroposterior, and mediolateral stability indices, in favor of the study group, after 3 mos of training ( P < 0.001).

CONCLUSIONS

Weight shift training combined with weight reduction was more beneficial than weight reduction alone in decreasing the risk of falling and fear of falling and improving isometric knee torque and overall, anteroposterior, and mediolateral stability indices. It could be used for treating balance problems and weakness around the knee joint in obese women.

TO CLAIM CME CREDITS

Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCME.

CME OBJECTIVES

Upon completion of this article, the reader should be able to: (1) Determine the impact of weight shift training on risk of falling and postural stability in obese women; (2) Identify the effect of weight shift training on fear of falling in adult women with obesity; and (3) Verify the additive effect of weight shift training to weight reduction program vs. weight reduction program alone on muscle strength in young obese women.

LEVEL

Advanced.

ACCREDITATION

The Association of Academic Physiatrists is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.The Association of Academic Physiatrists designates this Journal-based CME activity for a maximum of 1.0 AMA PRA Category 1 Credit(s) ™. Physicians should only claim credit commensurate with the extent of their participation in the activity.

Muscle coordination and recruitment during squat assistance using a robotic ankle-foot exoskeleton

Squatting is an intensive activity routinely performed in the workplace to lift and lower loads. The effort to perform a squat can decrease using an exoskeleton that considers individual worker's differences and assists them with a customized solution, namely, personalized assistance. Designing such an exoskeleton could be improved by understanding how the user's muscle activity changes when assistance is provided. This study investigated the change in the muscle recruitment and activation pattern when personalized assistance was provided. The personalized assistance was provided by an ankle-foot exoskeleton during squatting and we compared its effect with that of the no-device and unpowered exoskeleton conditions using previously collected data. We identified four main muscle recruitment strategies across ten participants. One of the strategies mainly used quadriceps muscles, and the activation level corresponding to the strategy was reduced under exoskeleton assistance compared to the no-device and unpowered conditions. These quadriceps dominant synergy and rectus femoris activations showed reasonable correlations (r = 0.65, 0.59) to the metabolic cost of squatting. These results indicate that the assistance helped reduce quadriceps activation, and thus, the metabolic cost of squatting. These outcomes suggest that the muscle recruitment and activation patterns could be used to design an exoskeleton and training methods.

Resistance Training for Patients with Cancer: A Conceptual Framework for Maximizing Strength, Power, Functional Mobility, and Body Composition to Optimize Health and Outcomes

There are many benefits to the addition of exercise to cancer treatment and survivorship, particularly with resistance training regimens that target hypertrophy, bone mineral density, strength, functional mobility, and body composition. These goals are best achieved through a series of individualized high-intensity compound movements that mirror functional mobility patterns and sufficiently stress the musculoskeletal system. As a result of adequate stress, the body will engage compensatory cellular mechanisms that improve the structural integrity of bones and muscles, stimulate metabolism and the immune system, optimize functional performance, and minimize mechanical injury risk. The current evidence suggests that application of the above exercise principles, practiced in a safe environment under expert observation, may offer patients with cancer an effective means of improving overall health and cancer-specific outcomes. The following article poses several important questions certified exercise specialists and physicians should consider when prescribing resistance exercise for patients with cancer.