Resistance training using a novel robotic walker for over-ground gait rehabilitation: a preliminary study on healthy subjects

Proposal of Wheeled Gait-Training Walker with Dual-Assist Arms and Preliminary Pelvis-Handling Control

To achieve good rehabilitation in a person, the amount of walking by the person must be increased. Herein, a compact wheeled gait-training walker with dual-assist arms for assisting pelvic motion is proposed. The training walker is constructed by modifying a commercial wheeled walker with armrests. Therefore, it can be used easily by patients to perform their daily activities at rehabilitation sites. The hardware system and controller of the proposed assisting arms are designed based on gait-assist motions conducted by a physical therapist. The dual arms can achieve a pelvis-assisting motion with five degrees of freedom. A trajectory-following control with virtual compliance is implemented for the arms. Gait-assisting experiments are conducted, in which the dual arms allow a pelvic-like plate to follow the trajectory of a reference pose while reducing the upper body’s weight resting on the armrests. A 20 N force on the armrests, which represents the upper-limb load, is reduced while the plate follows the trajectory, and the proposed gait-assisting controller is validated.

The "Journal of Functional Morphology and Kinesiology" Journal Club Series: Resistance Training

We are glad to introduce the Second Journal Club of Volume Five, Second Issue. This edition is focused on relevant studies published in the last few years in the field of resistance training, chosen by our Editorial Board members and their colleagues. We hope to stimulate your curiosity in this field and to share with you the passion for the sport, seen also from the scientific point of view. The Editorial Board members wish you an inspiring lecture.

Identifying the Effects of Assistive and Resistive Guidance on the Gait of Elderly People Using a Smart Walker

Progression of technology has expanded applications of smart walkers in clinical fields. However, it is essential to investigate the effects of different types of gait guidance in order to introduce smart walkers more widely throughout these fields. The purpose of this study was to identify the effects of assistive and resistive guidance on the gait of elderly people using a smart walker. Gait parameters, surface electromyography of lower limb muscles, and trunk acceleration were measured. The assistive guidance force significantly increased gait speed, step length, and cadence while increasing trunk acceleration variability. The same amount of resistive guidance force did not change gait parameters; instead, however, it restrained the speed-dependent increase of trunk acceleration variability in the mediolateral direction. An analysis of muscle activity suggested that the lower limb muscle activity could be increased by varying gait parameters including speed, step length, and cadence.

Functional resistance training during walking: Mode of application differentially affects gait biomechanics and muscle activation patterns

BACKGROUND

Task-specific loading of the limbs-termed as functional resistance training-is commonly used in gait rehabilitation; however, the biomechanical and neuromuscular effects of various forms of functional resistance training have not been studied systematically. This information is crucial for correctly selecting the appropriate mode of functional resistance training when treating individuals with gait disorders.

RESEARCH QUESTION

To comprehensively evaluate the biomechanical (i.e., joint moment and power) and muscle activation changes with different forms of functional resistance training that are commonly used in clinics and research using biomechanical simulation-based analyses.

METHODS

We developed simulations of functional resistance training during walking using OpenSim (Gait2354, 23 degrees of freedom and 54 muscles) and custom MATLAB scripts. We investigated five modes of functional resistance training that have been commonly used in clinics or in research: (1) a weight attached at the ankle, (2) an elastic band attached at the ankle, (3) a viscous device attached to the hip and knee, (4) a weight attached at the pelvis, and (5) a constant backwards pulling force at the pelvis. Lower-extremity joint moments and powers were computed using inverse dynamics and muscle activations were estimated using computed muscle control while walking with each device under multiple resistance levels: normal walking with no resistance, and walking with 30, 60, and 90 Newtons of resistance.

RESULTS

The results indicate that the way in which resistance is applied during gait training differentially affects the internal joint moments, powers, and muscle activations as well as the joints and phase of the gait cycle where the resistance was experienced.

SIGNIFICANCE

The results highlight the importance of understanding the joints and muscles that are targeted by various modes of functional resistance training and carefully choosing the best mode of training that meets the specific therapeutic needs of the patient.

Rowing Simulator Modulates Water Density to Foster Motor Learning

Although robot-assisted training is present in various fields such as sports engineering and rehabilitation, provision of training strategies that optimally support individual motor learning remains as a challenge. Literature has shown that guidance strategies are useful for beginners, while skilled trainees should benefit from challenging conditions. The Challenge Point Theory also supports this in a way that learning is dependent on the available information, which serves as a challenge to the learner. So, learning can be fostered when the optimal amount of information is given according to the trainee's skill. Even though the framework explains the importance of difficulty modulation, there are no practical guidelines for complex dynamic tasks on how to match the difficulty to the trainee's skill progress. Therefore, the goal of this study was to determine the impact on learning of a complex motor task by a modulated task difficulty scheme during the training sessions, without distorting the nature of task. In this 3-day protocol study, we compared two groups of naïve participants for learning a sweep rowing task in a highly sophisticated rowing simulator. During trainings, groups received concurrent visual feedback displaying the requested oar movement. Control group performed the task under constant difficulty in the training sessions. Experimental group's task difficulty was modulated by changing the virtual water density that generated different heaviness of the simulated water-oar interaction, which yielded practice variability. Learning was assessed in terms of spatial and velocity magnitude errors and the variability for these metrics. Results of final day tests revealed that both groups reduced their error and variability for the chosen metrics. Notably, in addition to the provision of a very well established visual feedback and knowledge of results, experimental group's variable training protocol with modulated difficulty showed a potential to be advantageous for the spatial consistency and velocity accuracy. The outcomes of training and test runs indicate that we could successfully alter the performance of the trainees by changing the density value of the virtual water. Therefore, a follow-up study is necessary to investigate how to match different density values to the skill and performance improvement of the participants.

Gait-phase-dependent control using a smart walker for physical training

Falling has become a key factor that affects the quality of life of the elderly. Currently, the use of a few rehabilitation robots can contribute to the restoration of balance. In this paper, a walker-based rehabilitation robot with a gait-phasedependent control algorithm is proposed to promote dynamic balance in the elderly. It has unique characteristics in that the level of the walker to resist the propulsion force exerted by a user can vary depending on the gait-phase that is estimated using the interaction force between the robot and the user. The robot efficiently improves the muscle power of various muscle groups of the user. Experiments with three young subjects were conducted to validate the effectiveness of the walker with the gait-phase-dependent control algorithm.

Design and Evaluation of a Motorized Robotic Bed Mover With Omnidirectional Mobility for Patient Transportation

Patient transportation in hospitals faces many challenges, including the limited manpower, work-related injuries, and low efficiency of current bed pushing methods. This paper presents a new motorized robotic bed mover with omnidirectional mobility to address this problem. This device is composed of an omnidirectional mobility unit, a force sensing-based human-machine interface, and control hardware with batteries and electronics. The proposed bed mover can be attached to the bottom of a manual hospital stretcher, transforming it into a powered omnidirectional bed (OmniBed) that can be used only by one person. The function of the OmniBed is compared with that of a conventional powered bed, which only provides forward assistance with a fifth powered wheel. We perform a pilot study with 14 subjects to evaluate the performance of this OmniBed and benefits for hospital application. The experimental results show that the OmniBed can half the manpower while decreasing back muscle activities, revealing the potential health benefits for older staffs. The OmniBed also shows the promising signs of high precision and handling in small spaces with its one-step "parallel-parking" ability. This device is more ergonomic, more effective, and safer than the conventional powered bed.