The road to Cybathlon 2016 - Functional electrical stimulation cycling Team IRPT/SPZ

Effects of releasing ankle joint during electrically evoked cycling in persons with motor complete spinal cord injury

Literature has shown that simulated power production during conventional functional electrical stimulation (FES) cycling was improved by 14% by releasing the ankle joint from a fixed ankle setup and with the stimulation of the tibialis anterior and triceps surae. This study aims to investigate the effect of releasing the ankle joint on the pedal power production during FES cycling in persons with spinal cord injury (SCI). Seven persons with motor complete SCI participated in this study. All participants performed 1 min of fixed-ankle and 1 min of free-ankle FES cycling with two stimulation modes. In mode 1 participants performed FES-evoked cycling with the stimulation of quadriceps and hamstring muscles only (QH stimulation), while Mode 2 had stimulation of quadriceps, hamstring, tibialis anterior, and triceps surae muscles (QHT stimulation). The order of each trial was randomized in each participant. Free-ankle FES cycling offered greater ankle plantar- and dorsiflexion movement at specific slices of 20° crank angle intervals compared to fixed-ankle. There were significant differences in the mean and peak normalized pedal power outputs (POs) [F(1,500) = 14.03, p < 0.01 and F(1,500) = 7.111, p = 0.008, respectively] between fixed- and free-ankle QH stimulation, and fixed- and free-ankle QHT stimulation. Fixed-ankle QHT stimulation elevated the peak normalized pedal PO by 14.5% more than free-ankle QH stimulation. Releasing the ankle joint while providing no stimulation to the triceps surae and tibialis anterior reduces power output. The findings of this study suggest that QHT stimulation is necessary during free-ankle FES cycling to maintain power production as fixed-ankle.

ICEP: An Instrumented Cycling Ergometer Platform for the Assessment of Advanced FES Strategies

BACKGROUND

Functional electrical stimulation (FES) cycling has seen an upsurge in interest over the last decade. The present study describes the novel instrumented cycling ergometer platform designed to assess the efficiency of electrical stimulation strategies. The capabilities of the platform are showcased in an example determining the adequate stimulation patterns for reproducing a cycling movement of the paralyzed legs of a spinal cord injury (SCI) subject.

METHODS

Two procedures have been followed to determine the stimulation patterns: (1) using the EMG recordings of the able-bodied subject; (2) using the recordings of the forces produced by the SCI subject's stimulated muscles.

RESULTS

the stimulation pattern derived from the SCI subject's force output was found to produce 14% more power than the EMG-derived stimulation pattern.

CONCLUSIONS

the cycling platform proved useful for determining and assessing stimulation patterns, and it can be used to further investigate advanced stimulation strategies.

Contributions of the Cybathlon championship to the literature on functional electrical stimulation cycling among individuals with spinal cord injury: A bibliometric review

BACKGROUND

Due to its clinically proven safety and health benefits, functional electrical stimulation (FES) cycling has become a popular exercise modality for individuals with spinal cord injury (SCI). Since its inception in 2013, the Cybathlon championship has been a platform for publicizing the potential of FES cycling in rehabilitation and exercise for individuals with SCI. This study aimed to evaluate the contribution of the Cybathlon championship to the literature on FES cycling for individuals with SCI 3 years pre and post the staging of the Cybathlon championship in 2016.

METHODS

Web of Science, Scopus, ScienceDirect, IEEE Xplore, and Google Scholar databases were searched for relevant studies published between January 2013 and July 2019. The quality of the included studies was objectively evaluated using the Downs and Black checklist.

RESULTS

A total of 129 articles on FES cycling were retained for analysis. A total of 51 articles related to Cybathlon were reviewed, and 14 articles were ultimately evaluated for the quality. In 2017, the year following the Cybathlon championship, Web of Science cited 23 published studies on the championship, which was almost 5-fold more than that in 2016 (n = 5). Training was most often reported as a topic of interest in these studies, which mostly (76.7%) highlighted the training parameters of interest to participating teams in their effort to maximize their FES cycling performance during the Cybathlon championship.

CONCLUSION

The present study indicates that the Cybathlon championship in 2016 contributed to the number of literature published in 2017 on FES cycling for individuals with SCI. This finding may contribute to the lessons that can be learned from participation in the Cybathlon and potentially provide additional insights into research in the field of race-based FES cycling.

OIDA: An optimal interval detection algorithm for automatized determination of stimulation patterns for FES-Cycling in individuals with SCI

Background

FES-Cycling is an exciting recreational activity, which allows certain individuals after spinal cord injury or stroke to exercise their paralyzed muscles. The key for a successful application is to activate the right muscles at the right time.

Methods

While a stimulation pattern is usually determined empirically, we propose an approach using the torque feedback provided by a commercially available crank power-meter installed on a standard trike modified for FES-Cycling. By analysing the difference between active (with stimulation) and passive (without stimulation) torques along a full pedalling cycle, it is possible to differentiate between contributing and resisting phases for a particular muscle group. In this article we present an algorithm for the detection of optimal stimulation intervals and demonstrate its functionality, bilaterally for the quadriceps and hamstring muscles, in one subject with complete SCI on a home trainer. Stimulation patterns were automatically determined for two sensor input modalities: the crank-angle and a normalized thigh-angle (i.e. cycling phase, measured via inertial measurement units). In contrast to previous studies detecting automatic stimulation intervals on motorised ergo-cycles, our approach does not rely on a constant angular velocity provided by a motor, thus being applicable to the domain of mobile FES-Cycling.

Results

The algorithm was successfully able to identify stimulation intervals, individually for the subject’s left and right quadriceps and hamstring muscles. Smooth cycling was achieved without further adaptation, for both input signals (i.e. crank-angle and normalized thigh-angle).

Conclusion

The automatic determination of stimulation patterns, on basis of the positive net-torque generated during electrical stimulation, can help to reduce the duration of the initial fitting phase and to improve the quality of pedalling during a FES-Cycling session. In contrast to previous works, the presented algorithm does not rely on a constant angular velocity and thus can be effectively implemented into mobile FES-Cycling systems. As each muscle or muscle group is assessed individually, our algorithm can be used to evaluate the efficiency of novel electrode configurations and thus could promote increased performances during FES-Cycling.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12984-022-01018-2.

Selective neural stimulation methods improve cycling exercise performance after spinal cord injury: a case series

BACKGROUND

Exercise after paralysis can help prevent secondary health complications, but achieving adequate exercise volumes and intensities is difficult with loss of motor control. Existing electrical stimulation-driven cycling systems involve the paralyzed musculature but result in rapid force decline and muscle fatigue, limiting their effectiveness. This study explores the effects of selective stimulation patterns delivered through multi-contact nerve cuff electrodes on functional exercise output, with the goal of increasing work performed and power maintained within each bout of exercise.

METHODS

Three people with spinal cord injury and implanted stimulation systems performed cycling trials using conventional (S-Max), low overlap (S-Low), low duty cycle (C-Max), and/or combined low overlap and low duty cycle (C-Low) stimulation patterns. Outcome measures include total work (W), end power (Pend), power fluctuation indices (PFI), charge accumulation (Q), and efficiency (η). Mann-Whitney tests were used for statistical comparisons of W and Pend between a selective pattern and S-Max. Welch's ANOVAs were used to evaluate differences in PFIs among all patterns tested within a participant (n ≥ 90 per stimulation condition).

RESULTS

At least one selective pattern significantly (p < 0.05) increased W and Pend over S-Max in each participant. All selective patterns also reduced Q and increased η compared with S-Max for all participants. C-Max significantly (p < 0.01) increased PFI, indicating a decrease in ride smoothness with low duty cycle patterns.

CONCLUSIONS

Selective stimulation patterns can increase work performed and power sustained by paralyzed muscles prior to fatigue with increased stimulation efficiency. While still effective, low duty cycle patterns can cause inconsistent power outputs each pedal stroke, but this can be managed by utilizing optimized stimulation levels. Increasing work and sustained power each exercise session has the potential to ultimately improve the physiological benefits of stimulation-driven exercise.

Comparing Spatially Distributed and Single Electrode Stimulation on Individuals with Spinal Cord Injury

It is still a challenge to delay the onset of fatigue on muscle contraction induced by Functional Electrical Stimulation (FES). We explored the use of two stimulation methods with the same total area, single electrode stimulation (SES), and spatially distributed electrical stimulation (SDSS) during isometric knee extension with spinal cord injured (SCI) volunteers. We applied stimulation on the left and right quadriceps of two SCI participants with both methods and recorded isometric force and evoked electromyography (eEMG). We calculated the force-time integral (FTI) and eEMG-time integral (eTI) for each stimulation series and used a linear regression as a measure of decay ratio. Moreover, we also estimated the contribution from each channel from eEMG.

Human enhancement through the lens of experimental and speculative neurotechnologies

Human enhancement deals with improving on and overcoming limitations of the human body and mind. Pharmaceutical compounds that alter consciousness and cognitive performance have been used and discussed for a long time. The prospect of neurotechnological applications such as brain-steered devices or using invasive and noninvasive electromagnetic stimulations of the human brain, however, has received less attention-especially outside of therapeutic practices-and remains relatively unexplored. Reflection and debates about neurotechnology for human enhancement are limited and remain predominantly with neurotech engineers, science-fiction enthusiasts and a small circle of academics in the field of neuroethics. It is well known, and described as the Collingridge dilemma, that at an early stage of development, changes can easily be enacted, but the need for changes can hardly be foreseen. Once the technology is entrenched, opportunities and risks start to materialize, and the need to adapt and change is clearly visible. However, carrying out these changes at such a late stage, in turn, becomes very difficult, tremendously expensive, and sometimes practically impossible. In this manuscript, we compile and categorize an overview of existing experimental and speculative applications of neurotechnologies, with the aim to find out, if these real or diegetic prototypes could be used to better understand the paths these applications are forging. In particular, we will investigate what kind of tools, motivations, and normative goals underpin experimental implementations by neurohackers, speculative designers and artists.

Stimulation of paralysed quadriceps muscles with sequentially and spatially distributed electrodes during dynamic knee extension

BACKGROUND

During functional electrical stimulation (FES) tasks with able-bodied (AB) participants, spatially distributed sequential stimulation (SDSS) has demonstrated substantial improvements in power output and fatigue properties compared to conventional single electrode stimulation (SES). The aim of this study was to compare the properties of SDSS and SES in participants with spinal cord injury (SCI) in a dynamic isokinetic knee extension task simulating knee movement during recumbent cycling.

METHOD

Using a case-series design, m. vastus lateralis and medialis of four participants with motor and sensory complete SCI (AIS A) were stimulated for 6 min on both legs with both electrode setups. With SES, target muscles were stimulated by a pair of electrodes. In SDSS, the distal electrodes were replaced by four small electrodes giving the same overall stimulation frequency and having the same total surface area. Torque was measured during knee extension by a dynamometer at an angular velocity of 110 deg/s. Mean power of the left and right sides (P_meanL,R) was calculated from all stimulated extensions for initial, final and all extensions. Fatigue is presented as an index value with respect to initial power from 1 to 0, whereby 1 means no fatigue.

RESULTS

SDSS showed higher P_meanL,R values for all four participants for all extensions (increases of 132% in participant P1, 100% in P2, 36% in P3 and 18% in P4 compared to SES) and for the initial phase (increases of 84%, 59%, 66%, and 16%, respectively). Fatigue resistance was better with SDSS for P1, P2 and P4 but worse for P3 (0.47 vs 0.35, 0.63 vs 0.49, 0.90 vs 0.82 and 0.59 vs 0.77, respectively).

CONCLUSION

Consistently higher P_meanL,R was observed for all four participants for initial and overall contractions using SDSS. This supports findings from previous studies with AB participants. Fatigue properties were better in three of the four participants. The lower fatigue resistance with SDSS in one participant may be explained by a very low muscle activation level in this case. Further investigation in a larger cohort is warranted.

EJTM3 is also covering Mobility and Medicine at large, an update

Since the first 2018 issue, the European Journal of Translational Myology expanded its authorship and readership from the strict topics of biology, physiology, diagnostic, management and rehabilitation of skeletal muscle to the more clinically relevant fields of human mobility to those of general medicine. This third issue opens with a review on Chronic Fatigue Syndrome, a very complex medical problem, as its other names testify (Myalgic Encephalomyelitis or Systemic Exertion Intolerance Disease). A more typical molecular myology original article follows (Increasing autophagy does not affect neurogenic muscle atrophy), but then several Rapid Reports cover different Medical Specialties fields, related or unrelated to neuromyology, mobility problems and their potential solutions. The Advisors of EJTM invite Authors to submit typescripts, taking into account that the journal is keen to publish high-level papers in the fields of Translational Myology, Mobility and Medicine at large.

Resting sympatho-vagal balance is related to 10 km running performance in master endurance athletes

Relationships between heart rate recovery after exercise (HRR, baseline heart rate variability measures (HRV), and time to perform a 10Km running trial (t10Km) were evaluated in "master" athletes of endurance to assess whether the measured indexes may be useful for monitoring the training status of the athletes. Ten “master” athletes of endurance, aged 40-60 years, were recruited. After baseline measures of HRV, the athletes performed a graded maximal test on treadmill and HRR was measured at 1 and 2 minutes from recovery. Subsequently they performed a 10Km running trial and t10Km was related to HRV and HRR indexes. The time to perform a 10Km running trial was significantly correlated with baseline HRV indexes. No correlation was found between t10Km and HRR. Baseline HRV measures, but not HRR, were significantly correlated with the time of performance on 10km running in “master” athletes. The enhanced parasympathetic function at rest appears to be a condition to a better performance on 10km running. HRV can be simple and useful measurements for monitoring the training stratus of athletes and their physical condition in proximity of a competition.

The Effectiveness of Functional Electrical Stimulation (FES) in On-Off Mode for Enhancing the Cycling Performance of Team Phoenix at 2016 Cybathlon

In this study we designed a Functional Electrical Stimulation (FES) trike for a female subject with spinal cord injury to exercise her lower limbs and improve her lower limb muscle condition for attending the 2016 Cybathlon FES bike competition. Our FES pilot was the only female participant, in the FES cycling competition and she rode for Team Phoenix from the Chinese University of Hong Kong. Due to the weakness of muscles in the lower limb of the subject, and due to scoliosis over her thoracolumbar aéra, the mechanical structure of the trike had to be tailor-made to ensure she sat on the bike in a safe and secure position. A six-phase angle-driven stimulation pattern was developed to stimulate quadriceps and hamstrings without gluteus muscles for contraction through four surface electrodes, thereby creating a cycling movement. To improve the cycling endurance and reduce the muscle fatigue, an on-off mode was developed for controlling the stimulation time that allowed the subject to cycle for 20s, then pause while the trike advanced without stimulation for 5s, followed by a subsequent 20 sec stimulation, to continue cycling. The pilot participated in the training procedure including training exercise at home, trike fitting in the trike by modifying the mechanical structure, and conducting the cycling exercise for six months. We observed significant improvements in the pilot’s lower limb condition. The on-off mode enabled our pilot to extend her cycling endurance effectively, from 1 min to 2.5 mins and the distance from 62m to 100m. Over the eight minutes time limit, our team successfully finished 100 m in the Cybathlon FES.

Cycle Training Using Implanted Neural Prostheses: Team Cleveland

Recently our laboratory team focused on training five individuals with complete spinal cord injuries for an overground FES bike race in the 2016 Cybathlon held in Zurich Switzerland. A unique advantage team Cleveland had over other teams was the use of implanted pulse generators that provide more selective activation of muscles compared to standard surface stimulation. The advancements in muscle strength and endurance and ultimately cycling power our pilots made during this training period helped propel our competing pilot to win gold at the Cybathlon and allowed our pilots to ride their bikes outside within their communities. Such positive outcomes has encouraged us to further explore more widespread use of FES overground cycling as a rehabilitative tool for those with spinal cord injuries. This review will describes our approach to this race including information on the pilots, stimulation strategy, bike details and training program.

Development of practical functional electrical stimulation cycling systems based on an electromyography study of the Cybathlon 2016

The purpose of this study was to develop a functional electrical stimulation (FES) system based on the motor driving concept for use by spinal cord injury patients participating in the FES Cycling competition at the Cybathlon 2016. The proposed FES system consists of a low-power control system, a precise processor unit, and a 4-channel stimulation unit. Self-adhesive carbon conductive electrodes were utilized for stimulation. A 26-year-old SCI patient was qualified to participate in the competition. The pilot patient underwent training for 16 months, which included experience with FES stimulation, performing FES cycling, and reducing spasticity, to practice using the FES system. In addition, using surface electromyography (EMG) during cycling, the muscle activation pattern for generating the stimulation profile was applied and resulted in good performance. The best FES cycling performance the pilot achieved was 1000 meters translation with the cycling system during twelve minutes of using the FES system. The pilot achieved an 1000 meters translation mobility within an average of 16 minutes of cycling. Nevertheless, the system must be further investigated regarding muscle fatigue and other factors that may affect the stimulation conditions.

Participation to the first Cybathlon: an overview of the FREEWHEELS team FES-cycling solution

This article is a contribution to a special issue aiming at collecting data and documenting the different specificities of the teams which participated into Cybathlon 2016 FES-bike discipline. Our team prepared one paraplegic pilot over one year and developed a FES-cycling device based on existing commercial products. Our pilot (47 y.o, spinal cord lesion T3 AIS A since year 1995) was qualified for the final race and finished in 6th position over 12 participants in the discipline, covering a total distance of 750m at an average speed of 5.71km/h, propelled by his own quadriceps and hamstrings muscles.

FES Bike Race preparation to Cybathlon 2016 by EMA team: a short case report

FES-assisted cycling has been recommended to people struggling to emerge from a disability to more functioning life after spinal cord injury. Recommendations issued by a gowing number of scientific papershas promised toimprove body composition and physical activity levels, as well as to controlinvoluntary muscle response; favoring activity and participation which break new grounds in expanding locomotion, leisure and occupational options for people with paraplegia and tetraplegia. In this report we described our experience to select and prepare a pilot to compete in the FES Bike Race modality at Cybathlon 2016 in Kloten (Zurick). He was a man, 38 years old, with a complete spinal cord injury, level T9, three years of injury. He took part in a two preparation phases lasting respectively 18 and 12 weeks each: (1st) pre-FES-cycling and a (2nd) FES-cycling. The 1st phase aimed to explore electrical stimulation response in the quadricps, hamstrings and gluteus muscles; searching for a standard muscular recruitment enable to propel the pedals of a trike. Following, in the 2nd phase, stationary to mobile FES-cycling was performed at the same time the development of the automation and control systems were being incorporated in the trike. We adapted a commercial tadpole trycicle anda pilot controlled system. Although we had planned a three session by week protocol, for reasons of term and time to finish the trike development and be prepared to compete, in the last two weeks before the Cybatlhon an intense level of exercise was maintained. After the race, we noticedinflammatory signs on the left knee which later revealed a patella fracture. The video footage analysis confirmed ithappened during the race's first lap.

Strategies and performances of Functional Electrical Stimulation Cycling using the BerkelBike with Spinal Cord Injury in a competition context (CYBATHLON)

The functional electrical stimulation (FES) bicycle race was an event at the Cybathlon, held in Zurich October 2016. BerkelBike BV (The Netherlands) in collaboration with Imperial College London entered a spinal cord injury pilot who had tetraplegia to compete in this event. The BerkelBike Pro is a commercially available FES capable recumbent which is normally driven by the arm- and leg power. The arm cranking part was disabled. Now the tricycle must be driven using the pilots own lower limb muscles through stimulation in accordance with race rules. The bike used during the race was also adapted with a fixed gear for improved efficiency. The pilot who represented this team come second place overall in the event and attained the fastest race time of all pilots who utilised surface electrode FES. Steps can be taken to increase the race efficiency of the BerkelBikes and its FES capabilities even further.

Functional electrical stimulation cycling strategies tested during preparation for the First Cybathlon Competition - a practical report from team ENS de Lyon

Whether it is from the patient’s or the physical therapist’s point of view, FES cycling can be considered either as a recreational activity, or an engaging rehabilitation tool. In both cases, it keeps patients with lower-limb paralysis motivated to sustain a regular physical activity. Thus, it is not surprising that it was selected as one of the six disciplines of the first Cybathlon competition held on October 8, 2016. However, many unresolved issues prevent FES cycling from being an activity practiced outdoors on a daily basis; such as, low power production, rapid muscle fatigue, precise electrode positioning, lack of systematic procedures to determine stimulation patterns, and the difficulty of transferring disabled riders from their wheelchair to the tricycle. This article documents the challenges we faced during preparation for the Cybathlon 2016 FES cycling race, and provides results obtained during different phases of the process. A particular specificity of our team was that, unlike most other teams where pilots were mainly paraplegic, both the primary and backup pilots for team ENS de Lyon are C6/C7 tetraplegics, with neither voluntary control of their abdominal muscles nor hand grip, and only partial use of their arms.