Улучшают ли упражнения на ногах функции рук и рук для лиц с нееврологическими расстройствами? Обзор.

Neurologic disorders such as stroke, Parkinson disease (PD), spinal cord injury (SCI), and amyotrophic lateral sclerosis (ALS) often impair upper extremity function, causing chronic impairments in activities of daily living (ADLs). Exploring effective upper extremity rehabilitation strategies is crucial to improving ADLs and transitioning to independent living.

To date, more emphasis in stroke, PD, SCI, and ALS rehabilitation has been placed on lower rather than upper extremity therapy. Early animal work identified autonomous neural networks in the spinal cord, termed central pattern generators (CPGs), which are responsible for rhythmic behaviors such as locomotion. 1 , 2 , 3 , 4 , 5 , 6 , 7 Further advances in quadruped animal models have revealed evidence for anatomically and functionally distinct cervical and lumbar CPGs for forelimbs and hindlimbs, which can be easily coupled or uncoupled depending on the task. 8 These circuits cooperatively integrate peripheral sensory, propriospinal, and descending supraspinal feedback mechanisms, ensuring effective task-dependent coordination of all four limbs during rhythmic activities. 4 , 9 , 10 , 11 , 12

Humans, although bipedal, retain evidence of inter-CPG communication between lumbar and cervical circuits, demonstrated during postural 13 and ambulatory perturbations, 14 recumbent leg stepping, 15 , 16 and with arm swing during normal gait. 17 The interlimb neural coupling is also highlighted by bidirectional reflex responses of the arms and legs, in which leg muscle Hoffmann-reflexes are modulated by arm position and vice versa. 18

Rehabilitation approaches have successfully leveraged inter-CPG communication, showing that arm swing or hand cycling can improve leg and gait function in individuals with neurologic conditions. 19 , 20 However, little research has focused on the reverse approach, using leg exercises to improve arm function, despite evidence that leg training can induce global experience-dependent plasticity, 21 and promote corticospinal excitability 22 in arm and hand muscles. Therefore, this scoping review aims to identify and describe studies of leg training with arm and hand outcomes in individuals with neurologic conditions by answering “Do leg-focused exercises improve arm and hand function for individuals with neurologic disorders?” The novelty of this topic necessitated a broad review to identify disparate studies with varying objectives, patient populations, and designs. Therefore, we determined that a scoping review was appropriate to address the research question.

Methods

Review methodology

The review followed the Joanna Briggs Institute (JBI) Scoping Review Methodology Groups guidelines 23 and the Preferred Reporting Item for Systematic Reviews and Meta-Analysis for Scoping Review guidelines and framework. 24 The review was not preregistered.

Research question

The research question “Do leg-focused exercises improve arm and hand function for individuals with neurologic disorders?” was developed using the Population/Concept/Context framework. 23

Selection process

The JBI and Preferred Reporting Item for Systematic Reviews and Meta-Analysis for Scoping Review frameworks also informed the inclusion and exclusion criteria ( table 1 ). On the basis of our preliminary search of relevant keywords, it was evident that we needed to increase the date range and number of databases searched. Because of limited resources, the search was restricted to English. Studies were excluded because of unclear interventions, or the inclusion of whole-body exercises as an intervention aside from those performed as part of inpatient standard of care, and where upper extremity outcome measures were not reported separately as part of a functional assessment (eg, International Standards for Neurological Classification of Spinal Cord Injury [Impairment Scale], Functional Independence Measure, Unified Parkinsons Disease Rating Scale [UPDRS]).

Search strategy

Author 1 (A1), Author 4 (A4), and Author 5 (A5) performed an initial citation search across multiple databases using citation mining, forward/backward citation searching, and author/group citation search strategies to narrow down the most appropriate terms used in the literature.

A medical librarian (Author 3, A3) performed comprehensive searches on November 29, 2023, and October 28, 2025, within five databases: PubMed, Embase (Ovid), Cumulative Index to Nursing and Allied Health Literature, Scopus, and Cochrane Central, including a gray literature search on November 29, 2023, within nine databases: Google Scholar (first 5 pages), medRxiv, Australia New Zealand Clinical Trials Registry, European Union Clinical Trials Registry, US government web-based resource ClinicalTrials.gov, ProQuest Dissertation/Theses, World Health Organization (WHO) Library, WHO Global Index Medicus, and WHO International Clinical Trials Registry Platform. The searches used proximity, adjacency, and/or exploded search strategies (a built-in database thesaurus for nested words), which concluded on November 18, 2025 ( table 2 , supplemental table S1 , available online only at http://www.archives-pmr.org/ ).

Author 2 (A2) and A5 hand-searched the reference lists of studies that met the inclusion criteria to identify additional records.

Information source handling

All peer-reviewed database sources were downloaded into Covidence, a reference management program. 25 Covidence handled duplications, visually inspected by A5. Following JBI guidance, a sample of 25 titles/abstracts was independently reviewed by A1, A2, A4, and A5. Reaching 88% agreement on the sample of 25 titles/abstracts, discrepancies were then discussed, and criteria were refined in table 1 for clarity. 23 Two reviewers (A1, A2, or A5) assessed each remaining article, with a third reviewer (A4) resolving conflicts. Inaccessible articles were excluded. The same workflow was applied to gray literature and secondary references.

Data charting

Key information was extracted into a charting table by one reviewer (A5) and confirmed by a second (A4): author(s), publication year, title, hypothesis, participant demographics, methodology, intervention type/duration, outcome measures, and key findings related to the research question. Methodological quality was evaluated using the Physiotherapy Evidence Database scale, 26 with classifications as “poor” (0-3), “fair” (4-5), “good” (6-8), or “excellent” (9-10).

Results

Study search and selection

The search identified 3531 records ( fig 1 ), with 2748 remaining after duplicate removal. After title and abstract screening, 2651 were excluded, leaving 97 for full-text review. Twelve peer-reviewed publications met inclusion criteria. Data from the 12 published studies are summarized in table 3 . Common reasons for exclusion were the absence of leg-focused interventions; unclear upper extremity outcomes; or failure to meet other criteria.

Did leg training support arm and hand rehabilitation?

Half of the included studies reported a statistically significant improvement or clinically relevant benefit in upper extremity function after a leg-focused intervention, whereas the remaining studies showed no change. No study reported negative effects on upper extremity function. Only one study specifically hypothesized improved upper extremity outcomes after lower extremity intervention. 37

Randomized controlled trials

Kwakkel et al 28 investigated the effects of arm and leg training intensities on functional recovery in 101 individuals with severe acute stroke. All participants received 20 weeks of usual care consisting of daily arm and leg rehabilitation (30 min), and ADL training (1.5 h/wk). Participants were randomly divided into an arm training (n=33), leg training (n=31), or control group (n=37), each receiving an additional 30 minutes (5/wk) of therapist-supervised sessions. Arm training consisted of leaning, punching a ball, grasping, and moving objects, and leg training consisted of sitting, standing, and weight-bearing exercises while standing and walking. The control group laid supine with the paretic limb passively immobilized by an inflatable pressure splint. An intention-to-treat analysis showed that additional arm training led to improvements in dexterity (Action Research Arm Test) of the paretic arm from week 12 onward (at wk 12: median [interquartile range] 3 [0-34] vs 0 [0-1] for controls, P <.05), compared with the control. In addition to significant improvements in walking performance, leg training resulted in improvements in upper extremity dexterity from week 6 onward (at wk 6: median 1 [0-43] vs 0 [0-1] for controls, P <.01), compared with the control ( table 3 ). At the 26-week follow-up, both training groups performed better in the Action Research Arm Test compared with the controls (median 0 [0-2.25] for controls vs 4 [0-38], P <.05 for arm training; vs 3 [0-56], P <.01 for leg training), with no significant difference between training groups. The authors attributed the improvements in arm function for the leg group to arm usage during gait training and the higher proportion of leg group participants with greater baseline dexterity. 28

Bourbonnais et al 30 assessed strength and muscle activation after a 6-week progressive force-feedback training program (60 min, 3/wk) in 25 individuals with chronic moderate stroke. Twelve participants performed isometric training of the paretic lower limb with 16 torque combinations exerted at the hip and knee. Thirteen participants performed isometric training of the paretic upper limb with 16 torque combinations exerted at the shoulder, elbow, and forearm with/without handgrip exertion. Assessments included a 12-meter self-paced walking velocity test, a 2-minute walk test, a timed Up-and-Go test, Modified Ashworth Scale (MAS), Fugl-Meyer Assessment (FMA), upper extremity test for the elderly, box and block test, finger-to-nose test, and a pain assessment. Both the leg- and arm training groups demonstrated similar upper limb improvements for FMA (F=4.21, P =.021), finger-to-nose (F=4.43, P =.026), and box and block (F=3.86, P =.04) assessments immediately after the intervention and at week 14 ( table 3 ). However, improvements did not translate into sustained functional gains. The authors postulated that this could be because of the lack of continued paretic limb use outside the study. 30

Johannsen et al 36 hypothesized that ten 30-minute sessions of bilateral leg training with rhythmic auditory cueing (BLETRAC) over five weeks would improve leg function and walking performance in chronic mild stroke. Twenty-one participants were randomly assigned to BLETRAC or a control group receiving bilateral arm training with rhythmic auditory cueing (BATRAC). Changes in FMA subscales served as their primary outcome, with a timed 10-Meter Walk Test (10MWT), treadmill walking parameters, and foot or hand aiming performance serving as secondary outcomes. No change was seen in either group for the FMA upper extremity subscale (0.2 [−6.0 to 6.4] vs 5.0 [−2 to 12], respectively; group main effect U=42.0, P =.36). Surprisingly, BLETRAC showed upper extremity improvements at week 6 in aiming tasks (mean increase of 2.6 for the paretic hand and 4.3 for the nonparetic hand), compared with BATRAC (mean increase 0.9 for the paretic hand and 2.1 for the nonparetic hand; group effect F 1,18 =2.15, P =.16) ( table 3 ). The authors noted this could be because of the generalization of motor learning or compensatory trunk control strategies. No change from baseline or difference between groups was found at the 3-month follow-up. 36

Fisher et al 34 evaluated eight weeks of high (n=10) versus low-intensity (n=10) leg exercises, in comparison with no-exercise (control; n=10), in individuals with PD. High-intensity exercise included 24 sessions of progressive body-weight–supported treadmill training (BWSTT), defined in terms of metabolic equivalents (METs). The high-intensity group aimed for over 3 METs or 75% of maximum heart rate, whereas the low-intensity group aimed for under 3 METs or 50% of maximum heart rate for 45 minutes. The control group consisted of six 1-hour educational classes in addition to customary daily exercise routines across eight weeks. Changes in UPDRS and functional performance measures (10MWT, sit-to-stand test) were compared before and after. A subset of participants from each group took part in additional transcranial magnetic stimulation testing of corticomotor excitability. Interestingly, the high-intensity group showed lengthened cortical silent period duration in an intrinsic hand muscle (average 32 ms increase for the more affected hemisphere vs average 19.4 ms increase for the less affected hemisphere) ( table 3 ), which is associated with reduced upper extremity PD symptoms, likely because of restoration of intracortical inhibition and facilitation. 39 The low-intensity and no-exercise groups did not show the same benefits. Because of the preliminary nature of the trial, authors only reported descriptive analysis, no inferential statistics were performed. However, the authors suggest that high-intensity leg-focused exercise may induce neuroplasticity in upper extremity circuits by restoring normal motor processing. 34

Ridgel et al 35 focused on the effects of “forced exercise” in 10 individuals living with mild to moderate PD. Participants who performed leg cycling at their preferred “voluntary exercise” rate (VE; n=5) were compared with a “forced exercise” group (FE; n=5), in which the preferred voluntary rate was increased by 30% on an instructor-led tandem bicycle. Both groups exercised at similar aerobic intensities for 60 minutes (3/wk, 8 wk). Aerobic fitness, PD symptoms, motor function, and bimanual dexterity were assessed at week 0, 8, and 12. Forced leg cycling led to immediate improvements in rigidity (41%), tremor (38%), bradykinesia (28%), responsible for improved motor function (35% compared with baseline, P =.002) at week 8 ( table 3 ), whereas no improvements were seen for the preferred cycling rate ( P >.17), despite both groups showing similar improvements in aerobic fitness. Grip-load profile plots improved for both upper limbs, interlimb coordination assessed by grip time delay improved significantly (F 2,46 =4.634, P =.015), and the rate of grip force for the manipulating hand increased significantly ( P =.006) for the FE group, with either no change (grip-load profiles, grip time delay) or a slight decrease (rate of grip force, P =.405) observed for the VE group. The FE group was significantly more consistent with digit placement of both stabilizing and manipulating limbs immediately after and at week 12 ( P <.01 for both), as opposed to the VE group that did not exhibit any improvement. Notably, biomechanical measures of bimanual dexterity persisted for weeks after intervention. The authors speculated that forced exercise leads to a shift in central motor control processes and enhanced coordination of upper extremity functionality after a lower extremity intervention. One implication is that forced exercise may result in increased general neuroplasticity, which therefore attenuates PD symptoms. 35

Dean et al 29 compared a 4-week (60 min, 3/wk) supervised, progressive lower limb circuit training program (n=5) with upper limb training (control; n=4) for improved locomotor function in nine individuals living with mild chronic stroke. All assessments were performed for both groups and included a 6-Minute Walk Test, 10MWT, timed Up-and-Go test, sit-to-stand, step test, as well as grip strength and hand dexterity. The leg-focused group showed significant immediate (wk 4) and retained (2-mo follow-up) improvements in walking speed and endurance, force production, and balance when compared with the arm-focused group. Despite significant improvements in walking and balance outcomes in the leg-focused group, neither group showed significant improvements from baseline when assessing changes in grip strength and dexterity. The authors suggested that the failure to demonstrate improvement in the upper limbs could have been because of the high level of skill needed, lack of sensitivity in preselected assessments, or insufficient baseline level of hand function. 29

Blennerhassett and Dite 31 investigated the impact of task-oriented practice on motor recovery in 30 individuals during inpatient rehabilitation after moderate stroke. In addition to usual care, both groups received an additional hour of limb-specific exercises for four weeks (5/wk). The leg group performed endurance, mobility, balance, stretch, and strengthening exercises of the lower limb, whereas the arm group performed stretch and strengthening exercises, functional arm and hand tasks, and hand-eye coordination activities. Hand function, spasticity, and mobility performance were assessed before, immediately after the intervention, and at a 6-month follow-up. Although both groups improved significantly across all mobility assessments (leg group: P< .02; arm group P <.006), only the upper limb group made significant improvements in upper extremity assessments (Jebsen-Taylor Hand Function Test: P= .005; MAS upper arm: P< .001) ( table 3 ). 31

Pang et al 33 assessed the effects of a community-based exercise program on paretic upper extremity function for 63 people with chronic stroke of varying severity. Participants were sex-matched and randomly divided into a therapist-supervised 19-week (60 min, 3/wk) arm or leg training group. Arm training consisted of progressive Theraband exercises, range of motion (ROM), weight-bearing activities, muscle strengthening, and functional activities. For participants unable to actively extend the wrist more than 20 degrees, 10-15 minutes of electrical muscle stimulation was performed on the wrist extensors. Progressive leg training consisted of walking, sitting, standing, alternate stepping, standing balance, partial squats, and toe raises. At week 19, the arm training group outperformed the leg group in the Wolf Motor Function Test of upper extremity function (functional ability score: between group, P =.003), and FMA (between group, P =.001) ( table 3 ), whereas the leg training group showed little to no improvement in upper extremity outcomes. Importantly, the authors noted that their study was underpowered. 33

Tyson et al 38 conducted a multicenter trial with 94 participants with mixed stroke severity using self-directed exercises during acute inpatient stroke care. In addition to usual care, participants undertook 30 minutes of daily (5/wk, 4 wk) mirror therapy for the upper limb (n=63) or exercises for the lower limb (n=31). Mirror therapy concentrated on the fingers, wrist, and elbow and included progressive ROM exercises and functional activities such as reaching, grasping, and moving objects. Leg exercises concentrated on the ankles, knees, and hips and included progressive ROM and functional activities such as sitting and standing. Many outcomes in muscle strength, sensation, dexterity, spasticity, balance, and neglect were assessed at weeks 0, 4, and 8. Smaller nonsignificant improvements in neglect, upper limb strength, and dexterity were observed after leg exercises, with greater nonsignificant improvements in sensation and upper limb activity, as compared with mirror therapy group; however, group differences were minimal relative to data variability (all P >.05) ( table 3 ). Lack of significance was attributed to the trial being underpowered with low reported adherence (totaling 5-15 min per session for 7 of the 28 d). 38

Nonrandomized controlled trial

Ridgel et al 37 showed that acute bouts of passive leg cycling significantly improved arm tremor and bradykinesia in 20 individuals with mild to moderate PD. A motorized bicycle was programmed to passively rotate the participants’ legs at 60, 70, or 80 revolutions per minute, randomly, across three cycling sessions (40 min; 1 wk apart). A control group (n=12) was later recruited for a single session to watch a short instructional video about the bicycle. Functional assessments were carried out before and within 10 minutes of completing each session (passive cycling, video watching). The UPDRS-III motor evaluation and kinematic data were collected to evaluate tremors and bradykinesia in the most affected arm. The cycling group showed improvements in arm tremor (0.25 decrease) and bradykinesia scores (hand grasp frequency: 0.10Hz increase; pronation/supination frequency: 0.18Hz increase), regardless of cycling rate, opposed to worsening scores in the control group, as reflected by significant group and time interaction effects (tremor P =.045; hand grasp P =.003; pronation/supination P =.000) ( table 3 ). The authors suggested that the acute improvements might be because of interlimb neural coupling and alterations in reflex pathways between arms and legs. 37

Case series

Hesse et al 27 investigated the efficiency of treadmill training compared with traditional “Bobath” physical therapy (also known as neurodevelopmental treatment), in a crossover study in seven nonambulatory individuals after stroke. The study used an A-B-A design, where “A” comprised 30 minutes of partial BWSTT, rapidly reduced to full weight-bearing if possible, and “B” 45 minutes of Bobath therapy, each phase lasting three weeks (15 sessions). The Bobath method focused on gait performance, ADLs, and upper extremity motor function. Outcomes included gait performance, motor function, upper and lower extremity strength, and ankle and wrist tone, as assessed by the functional ambulation category, 10MWT, the Rivermead Motor Assessment, the Motricity Index, and MAS, respectively. No changes in upper limb strength or tone were observed in either group ( table 3 ). 27

Mehrholz et al 32 evaluated the effects of a 6-week inpatient therapist-assisted jump training program (5-7 min; 5/wk) on measures of strength, spasticity, ROM, and gait in six individuals with hemiparesis and mild spasticity because of to stroke. The Motricity Index, FMA, modified Tardieu Scale, functional ambulation category, 10MWT, stride length, Rivermead Visual Gait Index, and 6-Minute Walk Test were measured at baseline and after six weeks. Despite significant improvement in multiple leg outcome measures, FMA remained unchanged over time for the upper limbs (39.5±2.1-39.2±2.0; P =.157) ( table 3 ). The authors noted that aside from a small sample size, the lack of upper extremity improvements might be because of the assistance provided during the jump (holding one arm), whereas the affected arm was secured in a sling to prevent microtrauma of the glenohumeral joint. 32

Discussion

To our knowledge, this is the first scoping review attempting to identify studies that may reveal the influence of leg-focused interventions on arm and hand function for individuals living with neurologic conditions. Of the 12 identified studies, six demonstrated statistically significant or clinically relevant benefits of leg training on upper extremity outcome measures, 28 , 30 , 34 , 35 , 36 , 37 mostly as incidental findings. This reveals a dearth of inquiry into the potential for lower extremity training to facilitate upper extremity rehabilitation.

Research on quadruped animal models provides strong evidence for neural coupling between forelimb and hindlimb circuits during ambulation of all types. 8 , 40 , 41 , 42 Humans retain several elements of this quadrupedal coupling, as seen in crawling, 43 walking, 10 , 44 running, cycling, 45 and swimming. 10 Disruption of these circuits leads to impaired coordination and altered reflex responses in both affected and unaffected limbs. 45 , 46 Despite extensive research exploring the use of interlimb connectivity to facilitate recovery, 47 , 48 , 49 , 50 , 51 , 52 little emphasis has been placed on using legs to improve arm function.

Interlimb coupling between legs

Studies in cats and rats have shown that isolated spinal networks are capable of generating rhythmic alternating flexion-extension movements in the hindlimbs even in the absence of supraspinal 53 , 54 and forelimb input, 55 demonstrating strong segmental coupling between the hindlimbs. In humans, leg-leg coupling is maintained during split-belt treadmill walking, where one leg moves at a different speed 56 , 57 , 58 or direction. 58 , 59 This complex coordination reflects a flexible interaction between supraspinal centers in the motor cortex, basal ganglia, cerebellum, spinal CPGs, peripheral sensory feedback, and descending supraspinal feedback loops that optimize leg movement during walking and other activities, even under extreme circumstances. 10 , 45

Interlimb coupling between arms

Studies with cats demonstrate that bilateral coordination of the forelimbs during locomotion is driven by cervical CPGs, similar to those controlling the hindlimbs. 11 , 60 , 61 As with quadrupeds, it is believed that humans have a distinct cervical CPG mediating upper limb coupling. Arm-arm coupling is evident during rhythmic tasks, such as arm swing during walking and arm cycling, where phase-dependent cervical spinal cord network modulation enables coordination between the arms. 62 , 63 Other tasks requiring bilateral power gripping—such as opening a bottle or lifting something heavy—involve coordinated neural coupling for force production and movement control. 64 However, arm-arm coupling is weaker than leg-leg coupling because of the greater demand for independent and versatile movements such as piano playing or fine object manipulation. 12 , 45 , 62 , 64 , 65 , 66

Interlimb coupling between arms and legs

Animal studies have shown that coordinated rhythmic movements of forelimbs and hindlimbs are controlled by distinct yet interconnected spinal networks that can operate autonomously from each other or supraspinal input. 8 , 53 , 67 , 68 , 69 In humans, arm-leg neural coupling is most evident during walking and running, where arm swing and leg movement are tightly coordinated. 10 , 45 , 70 Although locomotion can be achieved without propulsive arm activity, natural rhythmic patterns still occur, 12 even when arms are restrained, 71 or with varying perturbations on a split-belt treadmill, 72 and is strengthened as walking velocity increases. 73

Arm-leg coupling is also evident during nonwalking tasks such as arm-leg cycling and recumbent stepping, where active arm movement modulates leg reflexes and enhances neural activation and recruitment, 15 , 74 , 75 indicating bidirectional neural pathways for any type of rhythmic limb movement. 18 , 63 In fact, rhythmic hand-walking on an overhead treadmill while side-lying can induce locomotor-like activity in the legs. 76 Furthermore, reflexes in the arms can be modulated by rhythmic leg cycling, 65 and evoked by stimulation at the ankle. 18 Overall, these studies show patterns of preprogrammed rhythmic interlimb movements in line with the claim that human gait is still a form of quadrupedal locomotion 10 with bidirectional influence between arm and leg CPGs.

Interlimb coupling in neurologic disorders

Our scoping review supports the potential to leverage leg-focused training to improve upper limb function in people with neurologic disorders. However, exploiting this potential will require better understanding of interlimb coupling as a target for enhancing neurorehabilitation. In neurologic conditions such as SCI, rehabilitative strategies that engage both arms and legs have shown potential in re-establishing interlimb coupling and improving motor function. 45 For instance, arm swing during walking promotes more normal electromyographic patterns in leg muscles of individuals with incomplete cervical SCI. 20 Despite some poststroke hemiparesis studies showing exacerbated deficits in paretic leg coordination during nonparetic leg activity, 77 other studies have shown evidence of effective task transfer to impaired limbs, with improved neurologic function and walking performance across different interlimb training modalities. 78 , 79 , 80

With regard to individuals after a stroke, Kwakkel et al, 28 Bourbonnais et al, 30 and Johannsen et al 36 each showed that leg-focused rehabilitation improved upper limb performance to a greater degree than control interventions. In PD, Ridgel et al 35 , 37 demonstrated that 12 sessions of “forced” tandem-cycling and passive cycling at different training rates mitigated PD symptoms of upper extremity bradykinesia and tremors. Likewise, Fisher et al 34 observed increased corticomotor excitability projecting toward intrinsic hand muscles in addition to improved walking performance in individuals with PD undergoing high-intensity BWSTT (45 min; 3/wk; 8 wk), in comparison with low-intensity BWSTT or nil.

These studies provide evidence of bidirectional coupling and suggest that leg movements may facilitate motor recovery in the arms by enhancing overall neural plasticity. Although these studies hint at potential leg training benefits on arm function, not all studies showed improvement, and none specifically aimed to use leg training to improve upper extremity function. Factors such as study design, small sample size, poor adherence, training volume and intensity, sensitivity of upper limb assessments, as well as inclusion and exclusion criteria, could have impacted these results. Further research is needed to elucidate the role of leg exercises in facilitating arm and hand function across different neurologic conditions.

Study limitations

The purpose of the scoping review was to summarize the existing literature on an unexplored question rather than to definitively answer it. This review used a comprehensive search strategy across five primary databases, nine gray literature databases, and secondary references to ensure relevant studies were included. Systematic source handling and selection criteria were used to maintain objectivity. The findings highlight an underexplored topic, specifically leg-focused interventions for improving upper extremity outcomes, which warrants greater critical appraisal.

However, the lack of studies on this topic limits the strength of conclusions. Only 12 relevant peer-reviewed articles were identified across 77 years, and their methodological quality ranged from 5 to 8 on the Physiotherapy Evidence Database scale, with a score of 8 considered optimal for evaluating complex interventions such as exercise. 26 Included studies had heterogeneous designs, interventions, and outcomes. Many other studies were excluded because of unclear interventions, no leg-only training focus, or a lack of detailed upper extremity outcome measurements. No risk of bias assessment was conducted, limiting the strength of evidence. Furthermore, the review was open to any neurologic disorder; however, the identified studies were highly focused on stroke survivors and individuals living with PD, limiting generalizability to other neurologic conditions such as SCI.

Data revealing the potential influence of leg training on arm function were often an ancillary finding. Only six of the 12 studies reported improvements in upper extremity function, whereas the others reported no change. Considerable heterogeneity in study design, exercise parameters, outcome measures, and patient populations, along with small sample sizes, likely contributed to inconsistent findings, making it difficult to compare. Most studies lacked objective neurophysiology or radiological assessments (eg, neuroimaging, transcranial magnetic stimulation, electromyography), which are critical for assessing changes related to neural plasticity and interlimb coupling. Further understanding of how the stage of recovery, severity, and condition progression, as well as the duration and specific types of interventions, can influence the observed outcomes will be essential to interpret the findings and improve the design of subsequent trials.

Implications for further research

This review found evidence that leg training has the potential to improve arm and hand function in people with neurologic conditions. However, the extremely limited and heterogeneous nature of the results highlights significant gaps in our understanding of interlimb coupling from legs to arms as an innovative rehabilitation strategy. Further exploration of this approach is warranted not only in stroke and PD but also in other neurologic conditions, such as SCI, ALS, multiple sclerosis, and cerebral palsy.

Conclusions

This review highlights a critical gap in understanding the therapeutic impact of leg exercises on arm function and rehabilitation. Further research is needed to explore how various leg training modes, intensity, and frequency influence arm rehabilitation. Expanding this evidence with more objective measures could support integrating interlimb connectivity into routine neurorehabilitation for individuals living with neurologic conditions.

Disclosure

The investigators have no financial or nonfinancial disclosures to make in relation to this project.

Acknowledgments

Acknowledgments

The team would like to thank Katherine Santana, MA, MSLIS, from the Levy Library, Icahn School of Medicine at Mount Sinai, for their assistance in developing and implementing the preliminary search strategy.

Authorship contributions/CRediT statements

L.M.M. credited for conceptualization. L.M.M., N.Y.H., and K.S.N. defined the research question and eligibility criteria. G.W. performed the search strategy. K.S.N., L.M.M., L.E.K., and N.Y.H. reviewed the available literature. L.M.M. and N.Y.H. curated the data. K.S.N., L.E.K. and L.M.M. created the figures. L.M.M. wrote the original draft. N.Y.H., K.S.N., and L.M.M. performed second pass at writing. All authors contributed to revising and approving the final manuscript.

Data statements

The materials supporting the scoping review are included within the article (and its additional files).

Declaration of generative AI and AI-assisted technologies in the writing process

During the preparation of this work, the authors used ChatGPT 4.5 in order to correct grammatical errors and enhance the readability of the manuscript. After using this tool, the authors reviewed and edited the content as needed and takes full responsibility for the content of the publication.

Footnotes

L.M.M. and N.Y.H. are partially supported by a Spinal Cord Injury Model Systems grant [NIDILRR 90SIMS0003] and a Craig H. Neilsen Foundation grant [888233]. N.Y.H. is partially supported by the James J. Peters VA Medical Center. No other dedicated funding for this article.

Supplementary material associated with this article can be found, in the online version, at doi:10.1016/j.arrct.2025.100572 .

Supplementary materials

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