A review of different parameters of functional electric stimulation leg ergometry training in spinal cord injured individuals to formulate careful systematic comparisons between studies

The purpose of this paper is to understand the importance of considering the same or similar parameters in terms of functional electric stimulation-leg ergometry (FES-LE) study designing to formulate careful systematic comparisons between studies to provide spinal cord injury (SCI) patients with the best beneficial usages of FES-LE by developing injury-level specific standardized training protocols. This literature review is online based systematic research and most articles were obtained from online databases. Analyzing the studies included in these articles revealed that each study is different in numerous ways such as study designs, statistical methods, populations' demography, sample size, health measurements, clinical or laboratory techniques and data analysis methods. Dissimilarities in these parameters, along with their own individual limitations, and inconsistencies in the studies caused difficulties in making systematic comparisons and drawing reliable conclusions regarding the most significant effects and the best way of FES-LE usages in individuals with SCL Therefore, it is crucially important to develop a consensual standardized FES-LE training protocol for each heterogeneous group (e.g. acute vs. chronic; complete vs. incomplete; tetra vs. paraplegic) with its own homogeneous subjects (patients with similar demography). Quantifying the precise dose of stress, or determining the duration of FES intervention for each group of individuals with the same or similar level of injury and demography should also be documented in the standardized FES training protocol. Among different health assessments, measuring the muscle morphological changes (e.g. CSAf, fiber size, MHC) is very effective, as they directly refer to muscle strength improvements. Therefore, muscle morphological changes would be worth measuring in the standardized FES training studies. Hence, designing worldwide consensual injury-level specific standardized FES-LE training protocols would help the future studies to be constructed maintaining the same parameters and following consistencies; and thus, results from these studies could be used to formulate true systematic comparisons between them to determine the most effective usages of FES-LE in SCI individuals.