Physiological responses to moderate intensity continuous and high-intensity interval exercise in persons with paraplegia

Effect of high-intensity exercise training on functional recovery after spinal cord injury

Spinal cord injury (SCI) is a severe disorder of the central nervous system characterized by high prevalence and significant disability, imposing a substantial burden on patients and their families. In recent years, exercise training has gained prominence in the treatment of SCI due to its advantages, including low cost, high safety, ease of implementation, and significant efficacy. However, a consensus regarding the effects of various exercise training modalities and intensities on functional recovery in individuals with SCI remains elusive, and the efficacy and risks associated with high-intensity exercise training (HIET) are subjects of ongoing debate. Some studies have indicated that HIET offers superior therapeutic benefits, such as enhanced cardiovascular stress reflex sensitivity and increased release of neurotrophic factors, compared to moderate- or low-intensity exercise training. Nonetheless, HIET may entail risks, including secondary injuries, heightened inflammatory responses, and falls. This study reviews the positive and negative effects of HIET on various body systems in individuals with SCI, focusing on mechanisms such as neuroplasticity and immune regulation, to provide a theoretical basis and evidence for its prospective clinical application. Additionally, the limitations of existing studies are analyzed to inform recommendations and guidance for future research.

Post-processing Peak Oxygen Uptake Data Obtained During Cardiopulmonary Exercise Testing in Individuals With Spinal Cord Injury: A Scoping Review and Analysis of Different Post-processing Strategies

OBJECTIVES

To review the evidence regarding the most common practices adopted with cardiopulmonary exercise testing (CPET) in individuals with spinal cord injury (SCI), with the following specific aims to (1) determine the most common averaging strategies of peak oxygen uptake (V̇o2peak), (2) review the endpoint criteria adopted to determine a valid V̇o2peak, and (3) investigate the effect of averaging strategies on V̇o2peak values in a convenience sample of individuals with SCI (between the fourth cervical and sixth thoracic spinal segments).

DATA SOURCES

Searches for this scoping review were conducted in MEDLINE (PubMed), EMBASE, and Web Science.

STUDY SELECTION

Studies were included if (1) were original research on humans published in English, (2) recruited adults with traumatic and non-traumatic SCI, and (3) V̇o2peak reported and measured directly during CPET to volitional exhaustion. Full-text review identified studies published before April 2021 for inclusion.

DATA EXTRACTION

Extracted data included authors name, journal name, publication year, participant characteristics, and comprehensive information relevant to CPET.

DATA SYNTHESIS

We extracted data from a total of 197 studies involving 4860 participants. We found that more than 50% of studies adopted a 30-s averaging strategy. A wide range of endpoint criteria were used to confirm the attainment of maximal effort. In the convenience sample of individuals with SCI (n=30), the mean V̇o2peak decreased as epoch (ie, time) lengths increased. Reported V̇o2peak values differed significantly (P<.001) between averaging strategies, with epoch length explaining 56% of the variability.

CONCLUSIONS

The adoption of accepted and standardized methods for processing and analyzing CPET data are needed to ensure high-quality, reproducible research, and inform population-specific normative values for individuals with SCI.

Exercise intensity during exergaming in wheelchair-dependent persons with SCI

STUDY DESIGN

Cross-sectional study.

OBJECTIVES

It is challenging for persons with SCI, especially those who are wheelchair dependent, to find suitable and motivating aerobic exercise modes. Exergaming might be a good option, since it is relatively cheap and can be played at home, alone or with others. However, it is unknown if exergaming is performed at a sufficient exercise intensity.

SETTING

Sunnaas Rehabilitation Hospital, Norway.

METHODS

Twenty-two men and two women (n = 24) with chronic SCI (AIS A-C), all wheelchair users, were included during inpatient rehabilitation. All participant performed a maximal graded arm-crank test (pretest), while measuring peak oxygen uptake (VO2peak) and peak heart rate (HRpeak). The day after they had a practice playing session with three different exergames (X-box Kinect, Fruit Ninja; Nintendo Wii, Wii Sports Boxing; VR Oculus Rift, boxing). The following day, participants played each exergame for 15 min. During these 45 min of exergaming, exercise intensity, based on VO2peak and HRpeak from the pretest, was monitored.

RESULTS

Approximately 30 of the 45 min of exergaming was performed at moderate or high intensity. Participants exercised on average 24.5 min (95%CI 18.7-30.5) at moderate intensity (>50-80% VO2peak) and 6.6 min (95%CI 2.2-10.8) at high intensity (>80% VO2peak).

CONCLUSIONS

The participants were able to exercise at moderate or high intensity during exergaming in a considerable amount of time. Exergaming seems to be suitable for aerobic exercise at an intensity that can provide health benefits in wheelchair-dependent persons with SCI.

Benefits and interval training in individuals with spinal cord injury: A thematic review

BACKGROUND

Arm crank ergometry (ACE), functional electrical stimulation leg cycling exercise (FES-LCE), and the combination of the two (FES hybrid exercise) have all been used as activities to help improve the fitness-related health of individuals with spinal cord injury (SCI). More recently, high-intensity interval training (HIIT) has become popular in the non-disabled community due to its ability to produce greater aerobic fitness benefits or equivalent benefits with reduced time commitment.

OBJECTIVE

This thematic review of the literature sought to determine the potential benefits and practicality of using ACE, FES-LCE, and FES hybrid exercise in an interval training format for individuals with SCI.

METHODS

Systematic literature searches were conducted in May 2020 and March 2021 focusing on interval training in individuals with SCI. Pre-defined nested search terms were used to narrow the available literature from 4273 citations to 1362 articles. The titles and abstracts were then reviewed to determine the appropriateness of the articles ending with fifteen articles.

RESULTS

The literature was limited to fifteen articles with low participant numbers (n = 1-20). However, in each article, HIIT protocols either demonstrated a greater improvement in cardiovascular, metabolic, or practicality scores compared to moderate intensity continuous training (MICT) protocols, or improvement during relatively brief time commitments.

CONCLUSION

The available literature lacked sufficient numbers of randomized control trials. However, the available evidence is encouraging concerning the potential benefits and practicality of using HIIT (ACE, FES-LCE, or FES hybrid exercise) to improve aerobic and anaerobic capacity and decrease cardiometabolic risk after SCI.

Effects of Paraplegia Fitness Integrated Training on Physical Function and Exercise Self-Efficacy and Adherence Among Individuals With Spinal Cord Injury

Objective

To determine the effects of the Paraplegia Fitness Integrated Training (PARAFiT) program, which is an integrated graded physical exercise and health education program for individuals with spinal cord injury (SCI).

Methods

This nonrandomized single-blind study included 44 participants, who were assigned to either an intervention (PARAFiT) group or an active control (conventional physiotherapy) group. The intervention group underwent the PARAFiT program (8 weeks), which consisted of circuit-based interval training, progressive upper limb resistance training, and health education sessions. During the unsupervised period, the intervention group continuously underwent health education program once a month for 2 months (8 weeks). Repeated-measures analysis of variance was used for the analysis.

Results

The intervention group presented with a higher level of physical activity than did the control group; however, the difference was not significant (p=0.36). Additionally, the intervention group presented with better exercise self-efficacy and cardiorespiratory fitness and stronger bilateral shoulder muscle and handgrip than did the control group (all p<0.05). Exercise adherence was higher in the intervention group than in the control group during both the supervised (80% vs. 75%) and unsupervised (40% vs. 20%) periods.

Conclusion

The PARAFiT program enhanced the level of physical activity, exercise self-efficacy, physical fitness, and exercise adherence among the patients with SCI. Future studies should incorporate guidelines for home-based exercises and regular monitoring to promote long-term adherence to exercise and physical activity among individuals with SCI.

Hybrid high-intensity interval training using functional electrical stimulation leg cycling and arm ski ergometer for people with spinal cord injuries: a feasibility study

Aim

The aim was to assess safety and feasibility of Hybrid High-Intensity Interval Training (HIIT) using Functional Electrical Stimulation (FES) leg cycling and arm ski ergometer in people with Spinal Cord Injuries (SCI).

Method

Eight outpatients (mean age 42.8 years; 7 men) with stable SCI paraplegia (mean 14.5 years since injury) participated in hybrid HIIT (90% peak watts; 4 × 4–min intervals), three times a week (over 8 weeks). Primary outcomes were Adverse Events (AE), participant acceptability, shoulder pain, training intensity (% peak watts), and attendance.

Secondary outcomes were effect on peak oxygen uptake (VO₂peak) during FES hybrid poling, mean watts, self-reported leisure time physical activity, quality of life, and fatigue.

Results

No serious AE occurred; acceptability with the training modality was high, while shoulder pain increased by 9% (SD 95.2). During training, 50% of the participants reached > 90% peak watts during the intervals, three with the legs (FES cycle) and one with the arms (Ski-Erg). Overall, mean training intensity (% peak watts) was 92% (SD 18.9) for legs and 82% (SD 10.3) for arms. Proportion of fulfilled training minutes was 82% (range 36–100%); one participant dropped out after 6 weeks due to back pain. Mean VO₂peak increased by 17% (SD 17.5). Participants reported increased leisure time physical activity and health-related quality of life, besides reduced fatigue.

Conclusion

Hybrid HIIT was safe for people with SCI paraplegia. The majority of the criteria for feasibility were met with acceptable attendance rate, limited drop out, participants enjoyed training, and increased VO₂peak and mean watts. However, the intensity of 90% peak watts was reached by < 60% of the participants despite high RPE ratings during training. The method of measuring and calculating intensity needs to be studied further before a study using this HIIT protocol is undertaken.

Trial registration

Clinicaltrials.gov, NCT04211311, registered 12 December 2019 retrospectively registered

Supplementary Information

The online version contains supplementary material available at 10.1186/s40814-022-00997-2.

Virtual Strategies for the Broad Delivery of High Intensity Exercise in Persons With Spinal Cord Injury: Ongoing Studies and Considerations for Implementation

Spinal cord injury (SCI) results in a multitude of metabolic co-morbidities that can be managed by exercise. As in the non-injured population, manipulation of exercise intensity likely allows for fruitful optimization of exercise interventions targeting metabolic health in persons with SCI. In this population, interventions employing circuit resistance training (CRT) exhibit significant improvements in outcomes including cardiorespiratory fitness, muscular strength, and blood lipids, and recent exploration of high intensity interval training (HIIT) suggests the potential of this strategy to enhance health and fitness. However, the neurological consequences of SCI result in safety considerations and constrain exercise approaches, resulting in the need for specialized exercise practitioners. Furthermore, transportation challenges, inaccessibility of exercise facilities, and other barriers limit the translation of high intensity "real world" exercise strategies. Delivering exercise via online ("virtual") platforms overcomes certain access barriers while allowing for broad distribution of high intensity exercise despite the limited number of population-specific exercise specialists. In this review, we initially discuss the need for "real world" high intensity exercise strategies in persons with SCI. We then consider the advantages and logistics of using virtual platforms to broadly deliver high intensity exercise in this population. Safety and risk mitigation are considered first followed by identifying strategies and technologies for delivery and monitoring of virtual high intensity exercise. Throughout the review, we discuss approaches from previous and ongoing trials and conclude by giving considerations for future efforts in this area.

Exercise Interventions Targeting Obesity in Persons With Spinal Cord Injury

Spinal cord injury (SCI) results in an array of cardiometabolic complications, with obesity being the most common component risk of cardiometabolic disease (CMD) in this population. Recent Consortium for Spinal Cord Medicine Clinical Practice Guidelines for CMD in SCI recommend physical exercise as a primary treatment strategy for the management of CMD in SCI. However, the high prevalence of obesity in SCI and the pleiotropic nature of this body habitus warrant strategies for tailoring exercise to specifically target obesity. In general, exercise for obesity management should aim primarily to induce a negative energy balance and secondarily to increase the use of fat as a fuel source. In persons with SCI, reductions in the muscle mass that can be recruited during activity limit the capacity for exercise to induce a calorie deficit. Furthermore, the available musculature exhibits a decreased oxidative capacity, limiting the utilization of fat during exercise. These constraints must be considered when designing exercise interventions for obesity management in SCI. Certain forms of exercise have a greater therapeutic potential in this population partly due to impacts on metabolism during recovery from exercise and at rest. In this article, we propose that exercise for obesity in SCI should target large muscle groups and aim to induce hypertrophy to increase total energy expenditure response to training. Furthermore, although carbohydrate reliance will be high during activity, certain forms of exercise might induce meaningful postexercise shifts in the use of fat as a fuel. General activity in this population is important for many components of health, but low energy cost of daily activities and limitations in upper body volitional exercise mean that exercise interventions targeting utilization and hypertrophy of large muscle groups will likely be required for obesity management.