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Abstract

Individuals with hemiplegia using a coupled-crank arm cycle may experience nonparetic arm overcompensation and paretic arm resistance due to neuromechanical deficits. Technologies that foster independent limb contributions may increase paretic arm recovery for people post-stroke. To document in a single case study the effects of 8 weeks of training with a smart trainer arm ergometer on power output, pedal speed, pedal synchronicity, quality of life, enjoyment, and engagement. A longitudinal, mixed methods, case study design was used to examine physical and psychosocial changes in an individual post-stroke after an 8-week arm cycling program using the Advanced Virtual Exercise Environment Device (AVEED) in a non-immersive virtual exergaming environment. After a pretest visit, the cycling speed of each arm was collected with open-ended responses over 24 training visits. A posttest visit and semi-structured interview were conducted. The data were mixed for the training visits and posttest to draw meta-inferences. The participant cycled faster bilaterally and used his paretic arm more than at pretest during cycling after 8 weeks of training with the AVEED. The speed difference between his paretic and non-paretic arms steadily decreased and the participant reported increasing enjoyment and engagement over time. The device, environment, and intervention were rated as usable, and the participant attributed several functional improvements with his paretic arm to the program. The AVEED, combined with an exergaming platform, was successful in improving the cycling speed and paretic arm contribution of an individual post-stroke through an 8-week non-immersive virtual exercise environment program.

Keywords

post-stroke rehabilitation arm ergometry interhemispheric inhibition physical disability neurorehabilitation virtual exercise environment

Highlights

● The Advanced Virtual Exercise Environment Device improved the cycling speed and paretic arm contribution of a person post-stroke during an 8-week program.

● This intervention introduced a novel method of providing visual feedback to the user to encourage symmetrical arm use.

● Consideration should be made to improve the efficiency and accessibility of a virtual exercise environment intervention by conducting future work in a community setting.

Introduction

Post-stroke hemiparesis often leads to a decline in health and function due to reduced physical activity.¹ Secondary conditions, such as physical deconditioning, cardiovascular disease, and social isolation, exacerbate morbidity and mortality, significantly diminishing quality of life for this population.² However, exercise is clearly linked to the reduction of secondary conditions and improving health and function in people with disabilities, contributing significantly to overall physical and mental well-being, including for those with stroke.³ Specifically, cardiorespiratory exercise has the potential to enhance brain function and foster motor rehabilitation.^4,5

Despite these benefits, a multitude of barriers across individual, social and environmental levels influence physical activity participation and lead to decreased physical activity among people with physical disabilities.^6
-13 Thus, there is a critical need for safe, innovative, and affordable solutions for physical fitness for stroke survivors. Many adults post-stroke fail to recover the full use of their paretic arm, the arm weakened or partially paralyzed as a result of the stroke, which may lead to increased difficulty to participate in their community.^14,15 Upper extremity dysfunction is a common consequence of stroke, with approximately 35% to 40% of individuals experiencing upper limb weakness within the first few days post-stroke, and up to 75% showing impaired hand function 3 to 6 months later.^16,17 Studies suggest that nearly 50% of stroke survivors do not regain full functional use of the affected upper limb, leading to long-term limitations in daily activities and participation .^17,18

Recent research has explored the efficacy of bilateral versus unilateral upper extremity training in stroke rehabilitation. A systematic review and meta-analysis by Dembele et al found that bilateral upper limb training was superior to unilateral training in improving motor impairments and enhancing functional independence in daily activities.¹⁹ These findings suggest that bilateral training may be more effective in promoting recovery during the subacute phase of stroke.

In contrast, a study by Yuan et al investigated the effects of uni- versus bilateral upper limb robot-assisted rehabilitation.²⁰ The results indicated that both training modalities led to improvements in motor function and activities of daily living, with no significant differences between the 2 approaches. This suggests that the choice between unilateral and bilateral training may be tailored based on individual patient needs and preferences.

Bilateral upper extremity training has been shown to promote neuroplasticity and improve motor function in stroke rehabilitation. Engaging both limbs simultaneously can enhance interhemispheric connectivity and facilitate cortical reorganization, leading to improved motor control in the affected limb. For instance, bilateral movements may reduce interhemispheric inhibition and promote motor cortex disinhibition, thereby enhancing neural plasticity.²¹ Similarly, repetitive bilateral arm training with rhythmic auditory cueing improved motor function in chronic hemiparetic stroke patients, indicating the potential of bilateral training to induce functional reorganization of motor networks.²²

However, bilateral training may also have limitations. Some studies indicate that while bilateral training can improve proximal arm function, it may be less effective than unilateral training for distal functions, such as hand and finger movements.²³ Additionally, there is a risk of reinforcing maladaptive movement patterns if bilateral training is not properly tailored to the individual’s specific impairments and functional goals. Therefore, while bilateral upper extremity training offers promising avenues for enhancing neuroplasticity and motor recovery post-stroke, its implementation should be carefully considered to maximize benefits and minimize potential drawbacks.

Recent systematic reviews and meta-analyses have compared the efficacy of bilateral and unilateral upper extremity training in stroke rehabilitation. A study by Dembele et al found that bilateral upper limb training was superior to unilateral upper limb training in improving motor impairments, as measured by the Fugl-Meyer Assessment of Upper Extremity (FMA-UE), and functional independence in daily activities, as measured by the Functional Independence Measure (FIM), in individuals within the subacute phase of stroke.¹⁹

Conversely, a systematic review by van Delden et al. suggested that both training modalities yielded similar improvements in upper limb function, with the choice between bilateral and unilateral training potentially influenced by the severity of upper limb paresis and the timing of the intervention post-stroke.²⁴

These findings underscore the importance of tailoring rehabilitation strategies to individual patient profiles, considering factors such as the severity of impairment and the timing of intervention, to optimize recovery outcomes. Following a stroke, the non-lesioned cortex (ie, the side of the brain not directly damaged by the stroke) exerts inhibitory control over the lesioned cortex (ie, the stroke-affected or damaged side of the brain) and impairs motor performance during bilateral tasks, such as arm cycling.^25,26 To examine this phenomenon further we conducted a study to compare unilateral versus bilateral split crank cycling using the Advanced Virtual Exercise Environment Device (AVEED).²⁷ The AVEED was designed as an ergometer for people post-stroke (Figure 1). The ergometer utilizes separate flywheels so an individual’s paretic arm must contribute work that is independent of the nonparetic limb. The power output curves from an earlier study were examined, and the results indicated that post-stroke participants cycled faster with their paretic limb during unilateral versus bilateral arm cycling, which suggests the presence of a neural process such as interhemispheric interference that reduces the ability to recruit the paretic arm during bilateral exercise.²⁷ One proposed mechanism underlying this interference is interhemispheric inhibition, a process by which the hemisphere of the brain not affected by the stroke exerts excessive inhibitory influence on the stroke-affected hemisphere through connections between the 2 sides, potentially limiting motor output from the paretic limb.²⁸

Figure 1.

Participant using the Advanced Virtual Exercise Environment Device (AVEED).

The AVEED ergometer features resistance control, flexible exercise motion, and real-time physiologic performance monitoring. AVEED has the unique ability to selectively couple (ie, link together) or de-couple (ie, separate) arm inputs which enables the user to exercise at differing workloads on each extremity and to rotate the cranks synchronously or asynchronously. AVEED also acts as a “smart” trainer that can interface with virtual cycling platforms such as ZWIFT© through a wireless connection and can measure and record pedal speed in revolutions per minute (RPM) and power output in watts (W) for each arm. While the results of our previous work demonstrated the function of the AVEED as an arm ergometer, it is unclear how the device would perform when used as a smart trainer to control 2 separate riders.

Given these results and the unique abilities of AVEED to function as a smart trainer and measure contribution of each arm independently, the purpose of this case study was to determine the effects of 8 weeks of AVEED exercise training on cycling speed, cycling synchronicity, quality of life, enjoyment, and engagement in an individual post-stroke with upper body hemiparesis. In addition, perspectives of the participant and researcher regarding usability of the device were examined.

Materials and Methods

Virtual Environment

ZWIFT© is a virtual, interactive cycling program that allows users with a smart trainer device to log on and ride, train, and race in a non-immersive virtual exercise environment (www.zwift.com). When connected to a smart trainer, the user’s device serves as the controller and the software displays the user’s avatar as a virtual cyclist. The ZWIFT© program translates input data from the exercise device to the avatar’s speed and power on a virtual cycle course along with corrections for real-world conditions such as surface and incline gradient. As the user stationary cycles, progress is displayed and can be watched through the ZWIFT© application on an iPad, phone, or television screen. Users can choose from 12 different virtual worlds based on actual locations or fictitious renderings. ZWIFT© offers gamified elements like power-ups and promotes communication and interaction with other users through intra-ride messaging, symbols, actions (giving another ride a thumbs up in encouragement), and social media tagging.

Interface

For this protocol, we created 2 separate ZWIFT© accounts, establishing 2 distinct handcycling avatars, with each of AVEED’s arm pedals providing data to control a single avatar (Figure 2). The participant, while cycling on the AVEED, had the ability to simultaneously control both avatars, offering visual feedback of 2 riders cycling together. The avatar linked to the participant’s paretic left arm, using the left AVEED arm pedal, was designated a red jersey/handcycle and displayed on a 48″ Sony Smart TV placed 6′ from AVEED. The avatar connected to the non-paretic right arm had a blue jersey/handcycle and appeared on a 15″ laptop screen positioned to the right of the TV. Displaying the paretic arm’s avatar on the larger screen aimed to enhance participant focus on that side. The distinct jersey and handcycle color selection provided visual clarity between the avatars and the corresponding arms they represented. An image of the ZWIFT game with 2 rider avatars is provided in the Supplemental Materials (S1).

Figure 2.

Schematic showing the interface between devices used for the cycling protocol.

Participant Recruitment

Recruitment took place via flyer at local organizations serving individuals post-stroke and by direct contact with participants in previous studies. Inclusion criteria: Individuals post-stroke, age 19 to 75 years, and able to use both arms during arm cycling exercise. Exclusion criteria: Individuals who have no movement in 1 arm or have an injury that prevents safe use of 1 arm during exercise, in ability to complete a 10 revolution pre-test, unstable cardiovascular conditions, and inability to understand study directions.

The participant, referred to as Mr. Nova (pseudonym), was a 71-year-old male who enrolled in this study 3 years after experiencing a stroke in April 2020. As a result of the stroke, he presented with left-side hemiparesis but ambulated independently with the assistance of a cane. Despite reduced mobility on the left-side, Mr. Nova could complete upper body cycle rotations independently with both arms. Based on the bimodal data distribution exhibited in a previous study with the AVEED, we recruited and selected this case because they were unable to exceed a peak unilateral speed of 60 peak RPM (pRPM) with the paretic arm.²⁷

Baseline Measurements

After providing institutionally approved Institutional Review Board informed consent, Mr. Nova participated in an 8-week progressive cycling exercise program for 1-h 3 times per week. Participant height, weight, resting blood pressure (BP) and resting heart rate (HR) were measured. The National Institutes of Health Stroke Scale (NIHSS),^29,30 Stroke Specific Quality of Life Scale (SS-QOL),³¹ Mini-Mental State Examination (MMSE),³² and Fatigue Severity Scale (FSS)^33,34 were administered to provide a comprehensive evaluation regarding various aspects of quality of life, function, and health.

Baseline cycling speed measurements were obtained for both the paretic and non-paretic upper extremities utilizing the AVEED. Following the previously described AVEED settings and positioning,²⁷ Mr. Nova underwent familiarization with the handcycling movement. After a 5-min warm-up, the participant cycled bilaterally at maximum speed for 10 s, repeating the procedure unilaterally for both the non-paretic and paretic arms. Subsequently, the comfortable cycling speed was measured following a 5-min recovery period, during which he cycled at a comfortable pace for 10 s, both bilaterally and unilaterally.

Exercise Training Protocol

Upon arrival at the laboratory for each training visit, the participant was fitted with a Polar H7 chest-strap HR monitor (Polar H7, Polar Electro, Bethpage, NY, USA), and resting blood pressure was recorded. A member of the research team connected AVEED to both ZWIFT© accounts, and Mr. Nova selected a cycling route from the ZWIFT© Watopia virtual world. Following a 5-min warm-up, Mr. Nova received a target speed for the training session, with encouragement to surpass but not fall below it. The AVEED exercise protocol comprised four 5-min cycle exercise bouts at or above the target speed, while maintaining proximity between ZWIFT© handcycle avatars. A 5-min rest followed each bout, during which Mr. Nova reported rate of perceived exertion (RPE) on a scale of 1 to 10, along with enjoyment and engagement using a visual analog scale (VAS).^35
-37 The VAS featured 100 mm lines, with endpoints indicating most enjoyment or engagement on the right and least on the left. Mr. Nova marked his level of enjoyment and engagement during each exercise bout. The session concluded with audio recording open-ended questions about his experience and recording data on the training session from the AVEED. A conceptual framework for the 8-week intervention is shown in the Supplemental Materials (S2).

Post-Training Measurements

The final visit consisted of repeating the same baseline assessments, completion of the System Usability Scale (SUS), and a semi-structured interview. The SUS is a validated and reliable scale for evaluating subjective usability of newly developed devices and systems.^38,39 Finally, the participant shared feedback and perspectives of the 8-week intervention through a semi-structured interview.

Progressive Exercise Decision Tree

We established a 2-step decision process for determining when and how to increase the target speed for exercise bouts within a session (Figure 3). The first step involved comparing the participant’s actual speed to the target goal. The second step assessed the participant’s ability to pedal with both arms, synchronously, during the session. If the participant exceeded their target RPM in at least 3 out of 4 exercise bouts and maintained a speed difference of less than 10 RPM between the cycling avatars representing the paretic and non-paretic limbs in at least 3 out of 4 bouts, the target RPM for the next training visit would increase by 5 RPM. If these criteria were not met, the target RPM for the subsequent training visit would remain unchanged.

Figure 3.

Intervention progression decision tree.

Quantitative Data Analyses

Bilateral and unilateral speed data for each arm were smoothed to 1-s values using a moving average. Additionally, l/r arm speed difference was created by calculating the absolute value of difference between the left arm and right arm speed at each data point. For each bout, the bilateral and unilateral speed for each arm was calculated using the mean of minutes 2 to 4. To determine synchronicity, we calculated the mean of difference of values from minutes 2 to 4 for each bout. Quantitative data were analyzed for descriptive statistics. VAS values for enjoyment and engagement were transformed to a 0 to 100 score for each bout, and the mean of the 4 bouts was used to represent each domain for the respective training visit.

Qualitative Data Analyses

Qualitative data were obtained during the intervention from participant responses to guiding questions and researcher observations. Guiding questions and the semi-structured interview were administered from an interview guide created to elicit responses on the experience of using the AVEED, the virtual environment, and the overall intervention (Appendix 1). All audio recordings were transcribed and compiled.

Observations made by the researcher were written down during sessions and either addressed technical issues with the equipment or quotes and comments made by the participant during the exercise bouts. These written notes were digitally recorded and compiled along with the transcripts. A narrative case study approach was implemented, and the qualitative data were analyzed using thematic analysis.^40,41 Transcripts were coded by 2 members of the research team. After the initial coding, intercoder reliability was assessed using % agreement and considered acceptable if agreement exceeded 90%.⁴² Once reliability was established, a codebook was created based on all qualitative data. Themes and subthemes were extracted. Qualitative data were coded and analyzed in NVivo 14 (QSR International).

Mixed Methods Data Integration

The quantitative results and the qualitative findings were mixed for training visits and the post-test visit to expand understanding develop our interpretations in a convergent design.⁴³ We compared the participant’s cycling performance, enjoyment, and engagement collected during training visits with the participant’s responses at the end of each training session to draw meta inferences over time. Next, we mixed posttest results and findings separately to draw meta-inferences on the overall experience of the intervention. We identified areas of mixing that either confirmed, expanded or diverged from our understanding. Side-by-side comparisons were developed for training visits (Table 3) and post-test integration (Table 4) The data collection and integration process are provided in the Supplemental Materials (S3).

Results

Quantitative Results

During the 8-week exercise program, mean unilateral and bilateral speed increased. Coinciding with increased speed, the difference in speed between paretic and non-paretic arms was dramatically reduced indicating the potential of the AVEED to mitigate interhemispheric inhibition in an 8-week intervention (Figure 4).

Figure 4.

Pre test and Post test speed comparison.

Paretic arm peak speed increased by 32% (from 39 to 57 pRPM), and bilateral peak speed rose by 28%. Notably, comfortable bilateral speed nearly doubled, increasing by 48% (from 22 to 42 RPM), suggesting enhanced endurance and motor coordination. The paretic/nonparetic peak speed ratio increasing from 0.33 to 0.44.

This participant also improved the unilateral peak speed of their paretic arm, bilateral speed, stroke specific quality of life, and the participant rated the intervention system as usable. (Table 1) While our participant scored higher on the energy, mobility, and work productivity subscales of the stroke specific quality of life measure, their upper extremity function score was lower at posttest. Quality of life, measured using a stroke-specific scale, showed a modest 6% improvement overall (from 175 to 187), with notable gains in subscales related to energy, family, mobility, personality, and thinking (Figure 5). Mood (25) and self-care (25) remained stable, while upper extremity function and vision slightly declined. Work productivity improved from 4 to 6.

Table 1.

Pretest and Posttest Quantitative Data.

Measure	PRE	POST	Difference
Paretic arm peak speed (pRPM)	39	57	+32%
Nonparetic arm peak speed (pRPM)	120	131	+8%
Paretic/nonparetic arm peak	0.33	0.44	+0.11
Bilateral peak speed (pRPM)	43	60	+28%
Comfortable bilateral speed (RPM)	22	42	+48%
Quality of life (Stroke specific)	175	187	+6%
Energy subscale	9	11
Family subscale	11	14
Language subscale	21	22
Mobility subscale	10	14
Mood subscale	25	25
Personality subscale	11	14
Self-care subscale	25	25
Social Roles subscale	20	19
Thinking subscale	8	9
UE Function subscale	16	14
Vision subscale	15	14
Work productivity	4	6
System Usability Scale (0-100)	-	75	-

Note. PRE = pretest; POST = posttest.

Figure 5.

Pre test and Post test stroke specific quality of life comparison.

Mr. Nova’s Mini-Mental State indicated that he did not possess cognitive impairment. Finally, the System Usability Scale (SUS) score of 75 indicates good usability and user satisfaction with the intervention platform.

Qualitative Findings

Three main themes emerged from the qualitative data analysis (tester’s observation notes, participant feedback after every session, and the interview after the intervention), (1) Device use, (2) Virtual exercise environment, and (3) Progress. The domains, quotes and study timepoints are shown in Table 2.

Table 2.

Qualitative Findings.

Domain	Quote	Time
Device use	“Well, I couldn’t just lay back and just sit like this, right. I had to lean forward with my arm won’t stretch out far enough for me.” Mr. Nova	Posttest
	“Well, it’s it wasn’t hard to use. It’s just my physical limitations. I wasn’t able to use it like I really wanted to. And my movement in my left arm is nothing like my right arm. So, you know, it was kind of difficult, but it was OK and. Nothing strenuous or anything.” Mr. Nova
	“I know some people, it might not. It just depends on their handicap, you know, limitations they can do.” Mr. Nova
Virtual exercise environment
Competition	“Oh, yeah, yeah I haven’t had competition. Why I just do it just to be stubbed. Like playing poker without real money, no fun.” Mr. Nova	Week 4
Competition	“Well, I don’t know. It’s either way. I mean I think it would be enjoyable with somebody else too. I mean with me it’s pretty good. I enjoy it like that. Either way, I mean. It would be fine.” Mr. Nova	Week 4
Learning something new	“I’ve learned that they’re not reactive as much as you know. You’re turning this and he’s not reacting right away. Then he’s delayed a little bit. And then he’s shoot up there. So, I’m learning how to handle it. When you got to learn to figure. Things out I guess.” Mr. Nova	Week 4
Task completion	“Well, I enjoyed it. I enjoyed it, really. I mean, it’s a lot of fun. This competition, see if I can keep them together and I like them still. So, it’s it’s enjoyable.” Mr. Nova	Week 4
Task completion	“Participant enjoyed having a course that he could complete. Said it gave him a sense of purpose.” Tester note	Week 5
Task completion	“I was engaged.it makes you engaged and is actually engaging. I think keeping them together. That’s the whole thing, you know, and it’s trying to build this speed too.” Mr. Nova	Week 6
Enjoyment factor	“I guess I enjoy trying to climbing hills. I enjoy that I finished, I mean that that means a lot, you know, finish the course.” Mr. Nova	Week 7
Social engagement	“Well, I did pass the guy going up the hill. I had fun about that.” Mr. Nova	Week 8
Enjoyment factor	“You know you changing scenery and stuff and then just makes it interesting. Now, if I was just peddling on a blank screen, it wouldn’t be a bit fun.” Mr. Nova	Posttest
Progress	“Participant has noticed at home he is able to raise his paretic arm better to put on t shirts.” Tester note	Week 2
	“Well, like just driving here today, I was able to put my hand up and hold. I don’t remember doing that in a long time, putting my hand up on top of the up-steering wheel, driving with like the 2 hands. . . It on top, so that’s improvement. . . I turned mostly.” Mr. Nova	Week 3
	“Yeah, I noticed that I got more movement to this arm than I normally have. . .I’m able to use it some to push myself up trying to get up and things like that, I mean I hadn’t been able to get up real high. Like I won’t, but I it seemed like just certain things I could tell.” Mr. Nova	Week 6
	“I tied my shoes. I haven’t been able to do that for a long time actually. I mean I could type. I never get my hands down there, but I eventually could get my arms down there at the time.”	Posttest
	“I just say I think it was good mentally and physical and it’s fun. . .You can see yourself doing stuff so it’s you know, like they really put yourself in that it might be different, but you know. It was fun, like it was you know, it was. Yeah, I enjoyed it”	Posttest
	“I mean, I think it did progress as I got along. I could tell like it seemed like I was doing better. First week, you know, like I said, maybe just a tiny bit, you know, but eventually I could tell I was doing better.”	Posttest
	“Well, it’s it wasn’t hard to use. It’s just my physical limitations. I wasn’t able to use it like I really wanted to, and my movement in my left arm is nothing like my right arm.”	Posttest

Device Use

This theme discusses the participant’s perception of the device and his experience using the device. The participant had some difficulty using both his arms in the first session and this changed as the sessions progressed. However, he had to adapt his posture by leaning forward to fully use his upper body. He felt the device was not difficult to use but the limitation was due to his functional level associated with his disability. The participant noted that the handles used in the device worked for him, but he was skeptical if it might work for everyone. Mr. Nova remained positive about his participation and after having some arm soreness in the first 2 weeks of the study, all soreness subsided by week 3.

Virtual Exercise Environment

This theme discusses the participant’s perspectives on different aspects of the virtual exercise environment (Zwift) and how facilitated his sessions. The sub-themes that were used were based on the SELECT model.⁴⁴ Social engagement—The participant enjoyed being in a virtual environment with other people. Enjoyment factor—The participant felt the activity was enjoyable due to various aspects like competition, completing the task, and exploring new things. Learning something new—The participant learned to use the device based on the response from the virtual environment. Exploration—The participant explored new sceneries and riding in courses in the virtual environment. Competition—Participant liked competing in the virtual environment. Task completion—The participant enjoyed and felt engaged when given a task of keeping both arms together at the same pace throughout the cycling process. The participant’s favorite part of the environment was goal setting, such as exceeding a specific distance in a visit, where he was given a course to complete. Between weeks 4 and 6, the researchers began to introduce him to more information provided by the virtual environment such as the distance he cycled in a session and encouraged him to travel further while synchronously cycling.

Progress

This theme focuses on the participant’s progress during the intervention period. The 2 sub-themes that emerged were, progress using the AVEED and improvement in the participant’s function. The participant had difficulty using the device initially but felt positive about his progress throughout the intervention period in getting used to the device and navigating in the virtual gaming environment in different scenarios. The participant talked about an improvement in his range of motion and reduction in pain of the paretic arm. It was apparent to Mr. Nova that he improved his cycling over the course of the intervention and attributed several functional improvements to the progress he made, including functional improvements using his left arm in his daily activities.

The research team also encountered technical issues related to the connection between AVEED and the virtual exercise environment due to the wireless devices creating this vital link. Despite few technical glitches in the first 4 sessions, the participant felt the AVEED was enjoyable and engaging to use and it had good health benefits. When asked for suggestions to improve the device or the intervention experience, he consistently said he didn’t feel a need for anything major to be changed with either. He also noted that the research team provided strong encouragement. One suggestion was to have participants try to get more comfortable with a single course in the virtual environment before moving to a new course.

Mixed Methods Integration

Training Visits

The quantitative and qualitative data collected from training visits were mixed and analyzed. A joint display integrating the data collected during the training visits demonstrates key physiological changes over time accompanied with illustrative quotes from Mr. Nova is shown in Table 3.

Table 3.

Joint Display Comparing Training Visits.

Week	RPM left arm	L/R difference	Enjoyment	Engagement	Qualitative theme	Meta-inference
1	25	10	n/a	n/a	Device Use; Progress; Game Environment; Experience	His paretic arm met speed and difference goals but reported frustration in keeping his left arm cycling with right. Technical issues and confusion with visual in-game cues may have impeded performance. He is learning to process the in-game information with moderate enjoyment and engagement.
2	28	7	n/a	n/a
3	28	5	67	73
4	28	6	73	77	Device Use; Game Environment; Experience, Progress	Increased enjoyment and engagement and he believes the training is improving his function. Improvements in performance and cycling together. Increased enjoyment and engagement with goal attainment.
5	37	4	88	91
6	31	4	90	92
7	33	4	91	94	Game Environment; Experience; Progress; Device Use	He is seeking new goals and metrics, increased interest in environment, varying courses, and distance traveled to keep engaged. The improvements in cycling performance have decreased and his enjoyment and engagement have reached maximum score.
8	37	3	95	97	Game Environment; Experience; Progress; Device Use

Note. RPM = revolutions per minute; L/R = left arm/right arm.

During the first few weeks of the intervention, Mr. Nova demonstrated a rapid improvement in cycling as demonstrated by bilateral speed and l/r RPM difference; however, he reported some frustration with his left arm performance and muscle soreness. The mitigation of technical issues accompanied by reduction in soreness and stiffness by week 3 may account for the steadily increasing enjoyment and engagement values (Figure 6).

Figure 6.

Enjoyment, engagement, left versus right arm speed difference, and bilateral speed over time with illustrative quotes.

During middle weeks of 4 to 6, Mr. Nova began to refer to improvements in his paretic arm function more often and demonstrated a reasonable increase in cycling speed with an inverse drop in speed difference between arms. His reported enjoyment and engagement slowly and steadily increased since the first week of exercise and related this to his feelings of goal attainment.

During the final weeks of the intervention, weeks 7 to 8, Mr. Nova’s increases in cycling speed and decreases in l/r arm speed difference began to wane and Mr. Nova’s enjoyment and engagement demonstrated a ceiling effect. However, the l/r arm speed difference was maintained below the 10 RPM difference threshold that was established a priori and he expressed more interest in the challenge of cycling further and the desire to finish complete courses.

Posttest Visit Integration

The quantitative and qualitative data collected from posttest visit were mixed and analyzed. A joint display integrating the data collected during the final visit can be found in Table 4. In addition to perceived improved paretic arm function, Mr. Nova had a positive reflection on the overall experience of the intervention as he enjoyed using the AVEED device, the game-like nature of the virtual exercise environment, and the regular interactions with the research team. Despite feeling that his left arm still limited him, Mr. Nova found the AVEED easy to use, especially in the adaptability of the device.

Table 4.

Joint Display Comparing Pretest and Posttest Data.

Outcome	Quantitative result	Qualitative theme	Meta-inference
Paretic arm peak speed (pRPM)	+ 32%	Progress	Mr. Nova attributes several positive changes in function to his improved performance during the 8-week program.
Bilateral peak speed (pRPM)	+28%
Comfortable bilateral speed (RPM)	+48%
Quality of life (stroke specific)	+6%	Overall experience	Mr. Nova positively viewed his participation in the intervention.
System usability scale (0-100)	75	Device use	Mr. Nova found the AVEED usable.

Note. AVEED = Advanced Virtual Exercise Environment Device.

Once Mr. Nova was acclimated to cycling with the AVEED, understood the goals that were set for him, and developed familiarity with the virtual exercise environment, he found the experience more enjoyable and engaging. One diverging result is the minor reduction in upper extremity subscale score in the stroke specific quality of life measure, which appears to contradict his perceptions that he had improved the function of his paretic left arm (Figure 5).

The AVEED and the virtual exercise environment were usable together and the device was able to control 2 separate rider avatars simultaneously. The AVEED also allowed researchers to develop a progressively more challenging workload that initially induced muscle soreness but resided after the third week of the intervention. Anecdotally, the research team noticed the benefits provided by setting goals in additional in-game metrics that motivated Mr. Nova.

Discussion

This case study examined the utility of a new device that allowed an adult post-stroke to exercise both arms together (bilaterally) or separately (unilaterally) in a virtual exercise environment. The major objective was to promote paretic arm contribution to cycling with both arms synchronously. Additionally, we implemented a protocol that established weekly goals that were increasingly more challenging for the participant (incremental RPM).

Progress Trajectory

Our participant demonstrated an increase in performance quality during the exergaming sessions demonstrated by the paretic and nonparetic arms cycling at nearly equivalent speeds resulting in improvement in overall cycling speed. However, when assessed for peak speed performance after the 8-week period, the 2 arms still showed a significant difference in speed attained between paretic and nonparetic arms, albeit a smaller difference (improving from 33% to 44%; Figure 4). This increase is important because his pRPM speed at the end of training was close to the 60 RPM bimodal cutoff established from previous work.²⁷1282} With a target cycling speed of 60 RPM, a sample of 19 individuals post-stroke exhibited increases of hand-grip force (13%), flexor carpi radialis isometric strength (30%), and upper extremity muscle activation (18%) on their paretic side after 5-weeks of arm cycling training.⁴⁵

The difference in total score on the stroke specific quality of life scale did not exceed the minimal detectable change.⁴⁶ The increase in mobility and decrease in upper extremity function subscales did exceed the minimally clinically important difference threshold (Table 1).⁴⁷ It is unclear why a discrepancy between his upper extremity function score and his perception (self-reported) that his paretic arm function improved was observed in this case study. Many factors may account for this difference such as the specific wording of the quantitative and qualitative questions; however, research shows that rehabilitation can affect perceptions of functional change as effectively as functional measures.⁴⁸

AVEED and Virtual Exercise Environments

The AVEED and the virtual exercise environment were usable together and the device was able to control 2 separate rider avatars simultaneously to provide a visual representation of synchronous bilateral cycling. The high enjoyment scores noted by the participant using the AVEED to control a game-like virtual exercise environment is consistent with previous work with exergames.^49,50,51 Studies show that interventions featuring exergames can foster improvements in cardiorespiratory fitness, mobility, physical activity, and QOL among adults with limited mobility.³⁷ Mr. Nova’s excellent adherence to the intervention and preference for cycling in the virtual exercise environment is similar to the results of studies showing higher attendance, adherence, energy expenditure, and enjoyment to interactive cycling interventions compared to cycling alone.^52,53 It was important to ensure that the participant remained engaged throughout the intervention because engagement and enjoyment have been shown to affect exercise intensity.⁵⁴

Application of AVEED to a Rehabilitation Model

This single case study explored the effective use of a specialized arm cycle ergometer that allowed each arm to independently drive the crank speed. As such, it allowed for interface with a commonly used exergaming platform to develop a “competition” between the paretic and nonparetic arms visualized as 2 riders racing against each other, with the goal being to ride along at the same speeds. Because combined visual feedback and cycling is associated with improved mechanical effectiveness in adults post-stroke, this concept of providing feedback during exercise that encourages symmetrical arm use is a novel approach that can be used in the clinic.⁵⁵

The decision-making process developed for this intervention was successful in providing a progressively more challenging exercise protocol (weekly) that initially induced muscle soreness but did not overwhelm or injure the participant. However, the research team noticed the benefits provided by setting goals in additional in-game metrics that motivated the user. The progressive difficulty was focused on increasing pedaling speed because of the bimodal results of previous work and research showing that a higher cycling speed is important for developing aerobic capacity in stroke survivors.⁵⁶ Additionally, the reduction in l/r difference over 8 weeks is a promising result because rhythmic arm cycling training may improve interlimb connectivity and translate into improved lower extremity functional movements, and greater effects in lower extremity coordination.^45,57

Limitations

These results should be interpreted with caution. This work illustrates a pilot case study, and our findings cannot be generalized. These results need to be confirmed using a larger sample size in a future study. While our exercise progression tree was promising, future research should further explore the appropriate dosing of intensity and frequency. This intervention was limited to just 8 weeks, and our participant may have exhibited an increase in paretic arm speed with more training sessions; however, this study may not adequately capture the long-term benefits or challenges. While our participant reported a high usability score, a larger sample of 8 to 10 participants is necessary to establish usability across a range of participants with stroke.⁵⁸ Our case study demonstrated a reduction in l/r arm difference, but more work needs to be done to investigate if this translates into increased cycling synchronicity. Furthermore, although the results suggest that the intervention may have reduced interhemispheric inhibition, neurophysiological evidence was lacking. To identify the mechanisms that may underlie the improvements reported in this work, future studies should incorporate the use of measures such as symmetry and roughness indices.⁵⁹ While the participants in our previous work reported high usability of the AVEED device, this work only reports the usability of a single user and may not be generalizable. Future work could strive to make this intervention more efficient by conducting future studies in a community exercise center or rehabilitation clinic. Additionally, a community setting may enable researchers to assess how environmental features affect the user’s experience through competition, social interaction, or feedback mechanisms. To make the intervention more accessible, the size of the AVEED could be reduced for upper extremity cycling and used inside the participants’ own home. We did not assess cognitive outcomes in this work; however, due to our findings, future virtual exercise interventions should assess cognitive engagement, and the attentional demands required to engage in the activity.

Conclusion

The AVEED, combined with a virtual exercise environment was successful in improving the cycling speed and paretic arm contribution of an individual post-stroke through a virtual exercise environment 8-week program.

Supplemental Material

sj-docx-1-inq-10.1177_00469580251366158 – Supplemental material for An 8-Week Virtual Exercise Environment Intervention for People Post-Stroke: A Longitudinal Mixed Methods Single Case Study

Supplemental material, sj-docx-1-inq-10.1177_00469580251366158 for An 8-Week Virtual Exercise Environment Intervention for People Post-Stroke: A Longitudinal Mixed Methods Single Case Study by Christen J. Mendonca, Sangeetha Mohanraj, Rebecca R. Rogers, Laurie A. Malone, Mohanraj Thirumalai, James H. Rimmer and David A. Brown in INQUIRY: The Journal of Health Care Organization, Provision, and Financing

Footnotes

Appendix 1 Acknowledgements

We would like to acknowledge Lloyd Cooper and Foster Phillips of Push Product Design for designing the AVEED and developing the system to control the virtual exercise environment with the device.

ORCID iDs

Christen J. Mendonca

Rebecca R. Rogers

Laurie A. Malone

Ethical Considerations

This study was approved by the Ethics Committee of University of Alabama at Birmingham (IRB-300009387) on August 25, 2022. All participants provided written informed consent prior to enrollment in the study. This research was conducted ethically in accordance with the World Medical Association Declaration of Helsinki.

Author Contributions

Per CRediT, each author played the following roles:

• Christen J. Mendonca: 1, 2, 3, 5, 6, 7, 10, 11, 12, 13, 14

• Sangeetha Mohanraj: 1, 3, 4, 7, 8, 10, 12, 13, 14

• Rebecca R. Rogers: 3, 5, 6, 13

• Laurie A. Malone: 1, 4, 14

• Mohanraj Thirumalai: 1, 4, 8, 10, 14

• James H. Rimmer: 1, 4, 8, 14

• David A. Brown: 1, 2, 6, 10, 11, 13, 14

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

Declaration of Conflicting Interests

The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: The authors report there are no competing interests to declare. This work was supported under RERC RecTech funded by the National Institute on Disability, Independent Living, and Rehabilitation Research (NIDILRR grant number 90REGE0002).

Data Availability Statement

The data sets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.

Guarantor

Christen J. Mendonca, PhD

Geolocation Information

This study was conducted in Birmingham, Alabama within the United States of America.

Supplemental Material

Supplemental material for this article is available online.

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