Table 2. Study’s overall benefits and limitations.

Study	Reason for selection	Results and Benefits	Limitations
Bruyneel et al. (2022)	Detection of stability during the FRT with technological devices	The FRT shows valid parameters for assessing patients post-stroke, with reliability higher for center-of-pressure (CoP) length and velocity.	A control group is needed to understand brain injury’s impact on postural readjustments during unstable sitting balance and assess its predictive value for functional recovery.
Caimmi et al. (2022)	Detection of stability during the FRT with technological devices	The authors introduced a rehabilitation intervention using robot-assisted functional movements against gravity. The intervention showed excellent compliance and reduced impairment in chronic stroke patients, even at 6-month follow-up. The results suggest that reduced impairment leads to improved activity, laying the groundwork for further studies to confirm findings and determine the optimal dose–response curve.	The study has several limitations, including a small sample size, dropouts, and the lack of a control group. It is unclear if patients improved better than other therapies, whether more intensive treatment led to better results, and if the assessor was not blinded. Further studies are needed to verify hypotheses on neuroplasticity, and the conclusions are based on clinical measures. The robot is not commercially available for rehabilitation, but a new one has been developed for further study.
Ghahramani, Rojas & Stirling (2022)	Detection of stability during the FRT with technological devices	The study explores the impact of aging on motion strategy and chest and pelvis coordination during Functional Retraining (FRT). Results show decreased maximum angular rotation, dynamic time warping (DTW) cost, and coordination in older participants. The study suggests balance deficiency may increase fall risk in older individuals.	The study has limitations, including focusing solely on age and not considering other factors affecting balance and performance. It is still unclear what causes the more extensive mean continuous relative phase (CRP) in fallers. Future research should analyze the correlation between CRP and senility issues, categorize older participants based on fall history, and consider the imbalance in male and female participant groups. Further analysis of sex effects could be beneficial.
Moriyama et al. (2022)	Detection of functional ability during the FRT with technological devices	The study found that the large hip strategy (LHS) can achieve high FRT values without an increased center of pressure (COP) forward movement, but this doesn’t necessarily indicate high physical function. The LHS may not reflect COPE or physical function, while the Small Hip Strategy (SHS) might reflect the center of pressure excursion (COPE) and some physical functions.	This study involved older individuals who participated in a health promotion project and could walk independently without a cane. The physical function assessment showed they were functional and at a low risk of falling. However, the findings were not generalizable to older individuals with high fall risk. The study also did not examine the effect of sex and movement strategies on fall risk and the relevance of these strategies in other assessments.
Ayed et al. (2021)	Remote evaluation of the parameters related to FRT with technological devices	Two studies confirmed the linear correlation between Red Green Blue Depth (RGBD) devices and standard approaches for assessing balance tests. Corrected data showed no statistical differences between the two techniques. These studies are a first step towards implementing the system at home, with good repeatability and strong association with manual FRT, suggesting RGBD devices as a viable substitute for unsupervised balancing test measurement.	This study’s primary limitations are that the tests were carried out in a lab environment and that no patients were recruited for the research. It is also advised to conduct additional research before utilizing Red Green Blue Depth (RGBD) equipment to administer the test to selected individuals at home.
Dewar et al. (2021)	Detection of stability during the FRT with technological devices	The study confirms the validity of forward FRT, with concurrent validity confirmed for lateral FRT. However, face and content validity was only confirmed when reaching the NP side in children with cerebral palsy (CP). Qualitative descriptors should be added to the Kids-BESTest FRT criteria.	Statistically significant differences were found between children with and without cerebral palsy (CP). Future studies may need samples to distinguish between postural techniques adopted by children with varying degrees of CP severity, motor types, distributions, and ages. Future research should focus on dynamic functional tasks, therapies to enhance stability limits, and postural methods to modulate sitting stability.
Marchesi et al. (2021)	Detection of functional ability during the FRT with technological devices	The study examined trunk and contralesional arm muscles, finding asymmetric bilateral activations. Stroke survivors struggled to deactivate contralesional muscles, especially in the lateral direction. Repeated tasks improved reaching distance with increased trunk muscle activation. Reaching distance correlated negatively with time-up-and-go test scores.	This study focuses on the modified functional reach test in stroke survivors, focusing in two directions. The study’s small number of muscles limited understanding of complex coordinated patterns and synergic activations. Future research should include other muscles, trunk and leg muscles, and a more significant number of stroke survivors to understand differences due to impairment. The study also suggests that the modified functional reach test can be characterized quickly and paired with marker-less algorithms for movement analysis, which could be particularly useful during the pandemic.
Park, Son & Choi (2021)	Detection of stability during the FRT with technological devices	The study found that posture control training in the sitting position using a virtual reality (VR) program was more effective in improving sitting balance and trunk stability in non-ambulatory children with cerebral palsy (CP), suggesting the development of future interventions to enhance independent movement performance and quality of life.	The study’s limitations include a small sample size, inconsistent effects due to short intervention duration, and insufficient consideration of balance and daily life activities. The Wii program is limited to children with cerebral palsy (CP), but the study has high clinical value. Further research is needed to develop a rehabilitation-specific program and long-term virtual reality (VR) training.
Nozu et al. (2021)	Detection of functional ability during the FRT with technological devices	Posteromedial reach performance on unstable surfaces affects joint angles, COP, and COM, influenced by ankle movement strategies. Understanding somatosensory loss’s impact on dynamic balance tasks can help assess chronic ankle pathology.	The study has limitations, including the potential for foam pads to induce somatosensory disruption, altering ankle torque due to mechanical forces, and the need for ankle muscle electromyographic responses to understand movement control synergies. The sample size did not include people with pathology, and higher-end statistical models were not used to analyze all joints in a 3-dimensional motion-capture system. Additionally, the study cannot establish a minimally important change in movement control strategy for healthy people.
Son, Muraki & Tochihara (2022)	Detection of functional ability during the FRT with technological devices	The study reveals that increasing personal protective equipment (PPE) weight decreases mobility, physical performance, and functional balance. Obstacle courses and step-ups are validated tests for measuring mobility, while functional balance tests, mainly Functional Reflex Tests (FRT), are practical. The findings can guide researchers, firefighters, and manufacturers in evaluating PPE mobility and developing comfortable, enhanced PPE.	The study’s statistical significance may be limited due to the participants’ lack of firefighting experience and the testing of firefighter personal protective equipment (PPE) in Japan. The test methods proposed may not apply to different races, countries, sexes, or PPE designs. Further validation, considering race, sex, and firefighter status, is required.
Chen et al. (2020)	Detection of frailty syndrome based on FRT with technological equipment	The authors created a computerized platform for screening frailty syndrome tests, comparing prefrail and nonfrail groups. They developed a prefrail prediction equation, allowing for calculating FAT scores for elderly subjects, indicating frailty degree and progression rate.	The study has limitations due to the insufficient sample size of subjects and potential sampling bias. Four predictors of the prefrail stage were identified and used to develop the “prefrail prediction equation”, which allowed for calculating the FAT score to represent the degree of frailty of an elderly patient. The study also had a small age distribution, with only five subjects over 80 years old and one subject over 85 years old. The study suggests collaboration between experts from various areas is necessary to effectively assess and diagnose frailty syndrome, conduct swift screening and detection, and provide early intervention and treatment. Future studies should include more comprehensive physical function performance tests and elderly subjects to establish a more comprehensive frailty syndrome database.
Reguera-García et al. (2020)	Detection of stability during the FRT with technological devices	Individuals with diverse neurological pathologies and similar functional tests show varying results in pressure mapping, indicating postural control issues. These individuals require specific treatment approaches, such as modifying wheelchair inclination or using orthopedic pillows, to reduce pressure ulcer risk.	The study’s main limitation is its small sample size, mainly involving people with severe disabilities and dependence in the same care center. Future research should analyze larger samples and patients with other neurological pathologies. It’s crucial to establish a correlation between sitting position and functional impairment to understand pressure mapping results. Future research should focus on specific physiotherapy protocols for people with multiple sclerosis, Friedreich’s ataxia, and spinal cord injuries.
Santamaria et al. (2020)	Detection of functional ability during the FRT with technological devices	The study demonstrates the effectiveness of TruST-intervention in promoting functional and independent sitting in children with CP, GMFCS III-IV, and segmental trunk control impairments, demonstrating its potential to maximize trunk and reaching control abilities.	The therapeutic regimes for children were not discontinued, potentially preserving improvements during the 3-month washout period. A larger sample size is needed to test the generalization of postural and reaching control benefits to a similar cerebral palsy (CP) population. Randomized clinical trials are required to determine the superiority of TruST-intervention over matched-dose control therapies.
Fell et al. (2019)	Detection of functional ability during the FRT with technological devices	The authors have found a strong correlation between clinician and mobile app scores for FRT, indicating the potential for a mobile health app to provide clinicians with objective movement data for recovery. This data could help identify potential health risks and trigger timely interventions, thus reducing complications. The findings encourage further development and testing of mobile health systems.	The study suggests future research on mStroke with a focus on caregiver collaboration and user-friendliness. It means a larger sample size and a focus on adherence support, streamlined communication between patients and healthcare teams, early identification and mitigation of complications, and caregiver support. The study also highlights the potential of machine learning in app development for the NIHSS Motor Arm and Motor Leg tests. The study emphasizes the need for further development and refinement of these apps.
Fishbein et al. (2019)	Detection of stability during the FRT with technological devices	The study shows that Virtual Reality (VR)-based dual-task walking (DTW) can improve walking and balance in people after a stroke. It suggests combining different training sessions with multiple tasks using low-cost systems like SeeMe. VR systems also improve motivation and enjoyment during training, making them practical for community use. Smartphone technology could also be used to integrate tasks during treadmill activity. Further research is needed to determine the feasibility of these programs in different subpopulations and phases after stroke.	The study has limitations, including the lack of measurement of physiological changes or neurological mechanisms in the brain post-intervention. It suggests the need for future research to explore reactive postural control mechanisms and the significant heterogeneity in the damaged brain area, which could affect performance levels post-intervention.
Tanaka et al. (2019)	Detection of functional ability during the FRT with technological devices	The markerless motion capture system (MLS) with Kinect system was used to measure the angular displacement of hip and ankle joints, suggesting its potential for accurately classifying movement strategies in FRT.	The study has several limitations, including a focus on ankle and hip joint angles, which may change if a hip angle method is adopted. However, the markerless motion capture system (MLS) data was valid, and the error between MLS and marker-based motion capture system (MBS) was smaller in ankle angles. The study did not examine the relationship between movement strategy and reach distance, suggesting future studies should use MLS with Kinect data.
Verdini et al. (2019)	Detection of functional ability during the FRT with technological devices	The study demonstrates that the Nintendo Wii Balance Board can be effectively used for single-device measures during squat and functional reach tests, with high agreement with force plates (FP) data and low fixed biases. This low-cost device is particularly beneficial for research or clinical environments, as it accurately describes dynamic tasks like functional reach and squat tests, thereby promoting their use in research and clinical settings.	The percentage errors for center-of-pressure (COP)-parameters are consistent with those obtained without horizontal forces from force plates, indicating that the source of inaccuracy is device-dependent.
Bao et al. (2018)	Detection of stability during the FRT with technological devices	A preliminary study found that vibrotactile sensory augmentation for eight weeks improved balance performance in healthy older adults. Participants showed increased visual and vestibular reliance, static and dynamic balance, and no pain, injuries, or falls. It supports sensory augmentation as a potential telerehabilitation tool.	The clinical outcome measures of gait-related activities show limited improvements due to the absence of significant sensory augmentation during gait exercises and limited transfer effects from standing exercises.
Hsiao et al. (2018)	Detection of stability during the FRT with technological devices	The study suggests that the Kinect system can be a reliable alternative to traditional functional reach tests for assessing balance in older adults. It proposes two parameters of forward reach: maximum distance and maximal velocity at the halfway time. The results show a strong correlation between these parameters and traditional functional reach, measuring postural stability and static balance. However, the older group had lower maximal forward reach than the younger group. The Kinect system is simple, inexpensive, repeatable, and age-sensitive, and walking speed and grip strength are correlated with maximal velocity at the halfway time.	The study has limitations, including an oversimplified model for balance components, a focus on single-axis movement, a single facility for elderly persons, and arbitrary comparator outcome measures. Balance is a complex process that requires coordination and constant adjustment. Factors like acceleration and deceleration must be considered when evaluating an individual’s balance function. The study also lacks validity and reliability for using the velocity of forward reach as a dynamic balance function indicator. Further testing is needed for generalization.
Mengarelli et al. (2018)	Detection of functional ability during the FRT with technological devices	The study evaluates the performance of the Nintendo Balance Board (NBB) in assessing balance measures in Functional Regression Testing (FRT). NBB has high consistency and linearity, making it suitable for quantifying center-of-pressure (COP) trajectories and related measures. Noise affects all COP parameters, suggesting its use in various loads for FRT evaluations. The findings could enhance low-cost instrumentation for balance assessment, especially in medical environments like rehabilitation centers. NBB’s portability, affordability, and lack of dedicated staff suit home-focused scenarios.	Further research is needed to assess the inter-device variability and test-retest reproducibility of the Nintendo Balance Board (NBB) for full usability in FRT and clinical relevance evaluations.
De Luca et al. (2017)	Detection of stability during the FRT with technological devices	The study emphasizes the significance of considering all body schema in a rehabilitation robotic program rather than concentrating solely on the impaired side.	The study did not investigate treatment effects on a control group, and the therapists involved in the training were not blinded to the experiment’s goal, allowing them to help stroke survivors achieve established goals. The authors found similar motor synergies between two arms due to three factors: Armeo’s gravity support, restricted training to robotic joints, and a larger population of mildly impaired subjects. Changes in these factors may result in different results.
Williams et al. (2017)	Detection of stability during the FRT with technological devices	The authors developed a mobile health system called mStroke, which performs fall risk assessment using FRT. Three reach distance measures were tested on healthy adult subjects, confirming the system’s concept and feasibility.	Experimental results show promising results, but room for improvement is suggested for FRT function in mStroke. More motion sensors, like those on the shoulder or arm, could capture more detailed body movements.