Quantifying Arms and Legs Contributions during Repetitive Electrically-Assisted Sit-To-Stand Exercise in Paraplegics: A Pilot Study

Summary

Arms contribution in Sit-To-Stand (SitTS) is determined by the legs' muscle condition. Several compensating strategies were discovered in efforts to achieve complete SitTS cycles. These findings triangulate the spinal cord injury (SCI) persons' biomechanical measures with their subjective feeling of load borne by both their limbs throughout the SitTS approaches.

Abstract

Execution of Sit-to-Stand (SitTS) in incomplete spinal cord injury (SCI) patients involves motor function in both upper and lower extremities. The use of arm support, in particular, is a significant assistive factor while executing SitTS movement in SCI population. In addition, the application of functional electrical stimulation (FES) onto quadriceps and gluteus maximus muscles is one of the prescribed management for incomplete SCI to improve muscle action for simple lower limb movements. However, the relative contribution of upper and lower extremities during SitTS has not been thoroughly investigated. Two motor incomplete SCI paraplegics performed repetitive SitTS to fatigue exercise challenge. Their performance was investigated as a mixed-method case-control study comparing SitTS with and without the assistance of FES. Three sets of SitTS tests were completed with 5-min resting period allocated in between sets, with mechanomyography (MMG) sensors attached over the rectus femoris muscles bilaterally. The exercise was separated into 2 sessions; Day 1 for voluntary SitTS and Day 2 for FES-assisted SitTS. Questionnaires were conducted after every session to gather the participants' input about their repetitive SitTS experience. The analysis confirmed that a SitTS cycle could be divided into three phases; Phase 1 (Preparation to stand), Phase 2 (Seat-off), and Phase 3 (Initiation of hip extension), which contributed to 23% ± 7%, 16% ± 4% and 61% ± 6% of the SitTS cycle, respectively. The contribution of arms and legs during SitTS movement varied in different participants based on their legs' Medical Research Council (MRC) muscle grade. In particular, the applied arm forces start to increase clearly when the leg forces start to decline during standing. This finding is supported by the significantly reduced MMG signal indicating leg muscle fatigue and their reported feeling of tiredness.

Introduction

Sit-To-Stand (SitTS) is a significant movement in a human's activity of daily living (ADL). It is also a prerequisite for basic functional activities such as standing, transferring, and walking. For patients with incomplete spinal cord injury (SCI), paraplegics in particular, SitTS exercise is a crucial activity for their functional independence^1,2. This exercise is essential for independence training, which eventually helps SCI population to improve their quality of life. In order to perform a sufficient and adequate SitTS exercise, the knowledge regarding their biomechanics and muscle activity should be ....

Protocol

The SitTS exercise and informed consent in this manuscript are described under ethical consideration by University of Malaya Medical Centre Ethics Committee (2017119-4828)¹². Study procedures were explained in detail to each participant, and written informed consent was obtained before beginning the SitTS trial. This study was conducted as mixed-mode, where quantitative data were obtained using biomechanical analysis, whereas subjective scores were obtained from feedback sessions (of the participants) and audio recordings (of the researcher-participants interactions during the study). This pilot study compared the participant's contribution....

Results

A total of 399 and 463 SitTS trials were completed without and with FES assisted correspondingly. The trials that contributed to each set are tabulated in Table 2. The participants could perform more SitTS trials with the presence of electrical stimulation on their legs, i.e., FES. Overall, both participants managed to perform more SitTS trials with the aid of FES. This suggests that FES helps in stimulating participants' quadriceps to execute SitTS action in a prolonged period²⁰

Discussion

The current study demonstrated a bodyweight contribution in SCI individuals during SitTS exercise. This study presented SF as an essential assistive device for paraplegics to do a successful SitTS cycle. Moreover, an instrumented SF was developed to ensure the arms force can be assessed too²⁸. The application of MMG was added in the study to observe prime SitTS muscle that helps researchers to understand SitTS performance better. Furthermore, the feedback session enabled researchers to obtain insi.......

Materials

Name	Company	Catalog Number	Comments
Customade chair			A customade chair was built to following to the force plate's dimension.
FES RehaStim 2	Hasomed		A device that can stimulate electrical current towards the muscle.
FlexiForce A201	Tekscan, Inc., USA	Force ranges: 0-100 lbs. (440 N)	Force sensors is used to capture arms force at standing frame.
Foldable standing frame		Height: 70.0 cm - 90.0 cm.	A walking frame that was bought from local medical company.
Motion Analysis	Vicon Oxford, UK		A system that records kinematic and kinetics of the activity.
Serial port terminal application	CoolTerm	version 1.4.6; Roger Meier's	An application to record the force sensor data.
Vibromyography software	BIOPAC System Inc., USA	AcqKnowledge 4.3.1	A software to record and strore raw MMG data. It also function for offline analyses.
VMG transducers and BIOPAC Vibromyography system	BIOPAC System Inc., USA	BP150 and HLT100C	A device to measure muscle activity.