Patrick L. Jacobs

Exercise Recommendations for Individuals with Spinal Cord Injury

Persons with spinal cord injury (SCI) exhibit deficits in volitional motor control and sensation that limit not only the performance of daily tasks but also the overall activity level of these persons. This population has been characterised as extremely sedentary with an increased incidence of secondary complications including diabetes mellitus, hypertension and atherogenic lipid profiles. As the daily lifestyle of the average person with SCI is without adequate stress for conditioning purposes, structured exercise activities must be added to the regular schedule if the individual is to reduce the likelihood of secondary complications and/or to enhance their physical capacity. The acute exercise responses and the capacity for exercise conditioning are directly related to the level and completeness of the spinal lesion. Appropriate exercise testing and training of persons with SCI should be based on the individual’s exercise capacity as determined by accurate assessment of the spinal lesion. The standard means of classification of SCI is by application of the International Standards for Classification of Spinal Cord Injury, written by the Neurological Standards Committee of the American Spinal Injury Association. Individuals with complete spinal injuries at or above the fourth thoracic level generally exhibit dramatically diminished cardiac acceleration with maximal heart rates less than 130 beats/min. The work capacity of these persons will be limited by reductions in cardiac output and circulation to the exercising musculature.Persons with complete spinal lesions below the T10 level will generally display injuries to the lower motor neurons within the lower extremities and, therefore, will not retain the capacity for neuromuscular activation by means of electrical stimulation. Persons with paraplegia also exhibit reduced exercise capacity and increased heart rate responses (compared with the non-disabled), which have been associated with circulatory limitations within the paralysed tissues. The recommendations for endurance and strength training in persons with SCI do not vary dramatically from the advice offered to the general population. Systems of functional electrical stimulation activate muscular contractions within the paralysed muscles of some persons with SCI. Coordinated patterns of stimulation allows purposeful exercise movements including recumbent cycling, rowing and upright ambulation. Exercise activity in persons with SCI is not without risks, with increased risks related to systemic dysfunction following the spinal injury. These individuals may exhibit an autonomic dysreflexia, significantly reduced bone density below the spinal lesion, joint contractures and/or thermal dysregulation. Persons with SCI can benefit greatly by participation in exercise activities, but those benefits can be enhanced and the relative risks may be reduced with accurate classification of the spinal injury.

Circuit training provides cardiorespiratory and strength benefits in persons with paraplegia

PURPOSE This study tested the safety and the effects of circuit resistance training (CRT) on peak upper extremity cardiorespiratory endurance and muscle strength in chronic survivors of paraplegia due to spinal cord injury. METHODS Ten men with chronic neurologically complete paraplegia at the T5-L1 levels participated in the study. Subjects completed 12 wk of CRT, using a series of alternating isoinertial resistance exercises on a multi-station gym and high-speed, low-resistance arm ergometry. Peak arm ergometry tests, upper extremity isoinertial strength testing, and testing of upper extremity isokinetic strength were all performed before and after training. RESULTS None of the subjects suffered injury from exercise training. Significant increases were observed in peak oxygen consumption (29.7%, P < 0.01), time to fatigue (P < 0.01), and peak power output during arm testing (P < 0.05). Significant increases in isoinertial strength for the training maneuvers ranged from 11.9% to 30% (Ps < 0.01). Significant increases in isokinetic strength were experienced for shoulder joint internal rotation, extension, abduction, adduction, and horizontal adduction (Ps < 0.05). CONCLUSION Chronic survivors of paraplegia safely improve their upper extremity cardiorespiratory endurance and muscle strength when undergoing a short-term circuit resistance training program. Gains in fitness and strength exceeded those usually reported after either arm endurance exercise conditioning or strength training in this subject population.

Circuit resistance training improves the atherogenic lipid profiles of persons with chronic paraplegia.

Abstract Background: People with chronic paraplegia frequently experience dyslipidemias characterized by depressed levels of high-densitylipoprotein cholesterol (HDL-C) and elevated levels of low-density lipoprotein cholesterol (LDL-C). These anormal lipid profiles andpoor fitness levels increase their risk for cardiovascular disease. Methods: To test the hypothesis that circuit resistance exercise training improves both upper-extremity fitness and the atherogenic lipid profile in persons with chronic paraplegia, a homogeneous cohort of 5 men with neurologically complete spinal cord injuriesat T6 to L 1 underwent 3 months of exercise training using uninterrupted resistance and endurance exercises of the upper extremities.Training was performed 3 times a week on alternating days. Results: Results of graded arm exercise testing showed a 30.3% improvement in peak oxygen consumption (P ° .01 ), a 33.5% increasein time to fatigue (P ° .01) and a 30.4% increase in peak power output (P <.05). Pretraining total cholesterol levels (TC) were in thelow-risk category and were nonsignificantly lowered following training. Similar nonsignificant reductions of plasma triglycerides averaging12 mgldL were attained. Conversely, a 25.9% lowering of LDL-C (P <.05) and 9.8% elevation of HDL-C (P <.05) were observed aftertraining. These changes reduced the average LDL-C- to- HDL-C ratio by 1 unit (P <.05) and the TC-to- HDL-C ratio from 5.0 ± 1.1(mean ± SO) to 3.9 ± 0.7 (P <.05). Conclusions: This change reflects a cardiovascular risk reduction of almost 25%; the TC/ HDL-C declined from the high-risk scoreof 5.0 to near the desired score of 3.5. These findings support the beneficial effects of circuit exercise resistance training on fitnessand atherogenic lipid profiles in persons with chronic paraplegia.

Evaluation of a training program for persons with SCI paraplegia using the Parastep 1 ambulation system: part 3. Lack of effect on bone mineral density.

OBJECTIVE To determine if the bone mineral density loss seen after spinal cord injury (SCI) is reversed by a walking program using the Parastep 1 system. DESIGN Before-after trial. SETTING Human SCI applied research laboratory. PARTICIPANTS Thirteen men and 3 women with thoracic motor- and sensory-complete SCI, mean age 28.8yrs, mean duration postinjury 3.8yrs. INTERVENTION Thirty-two functional neuromuscular stimulation (FNS) ambulation training sessions using a commercially available system (Parastep 1). This system consists of a microprocessor-controlled stimulator and a modified walking frame with finger-operated switches that permit the user to control the stimulation parameters and activate the stepping. OUTCOME MEASURE Bone mineral density at the femoral head, neck, and Wards triangle measured using a Lunar DP3 dual-photon densitometer. RESULTS No significant change in bone mineral density was found using repeated measures analyses of variance. CONCLUSIONS Axial loading combined with muscle stimulation and resistive exercise does not result in significant changes in bone mineral density in persons with complete paraplegia.

Acute enhancement of lower-extremity dynamic strength and flexibility with whole-body vibration.

Jacobs, PL and Burns, P. Acute enhancement of lower-extremity dynamic strength and flexibility with whole-body vibration. J Strength Cond Res 23(1): 51-57, 2009-The purpose of this investigation was to examine the acute effects of whole-body vibration (WBV) on muscular strength, flexibility, and heart rate (HR). Twenty adults (10 men, 10 women) untrained to WBV participated in the study. All subjects completed assessment of lower-extremity isokinetic torque, flexibility, and HR immediately before and after 6 minutes of WBV and 6 minutes of leg cycling ergometry (CYL), in randomized order. During WBV, subjects stood upright on a vibration platform for a total of 6 minutes. Vibration frequency was gradually increased during the first minute to a frequency of 26 Hz, which was maintained for the remaining 5 minutes. During CYL, power output was gradually increased to 50 W during the first minute and maintained at that power output for the remaining 5 minutes. Lower-extremity flexibility was determined using the sit-and-reach box test. Peak and average isokinetic torque of knee extension and flexion were measured by means of a motor-driven dynamometer with velocity fixed at 120°·s−1. Change scores for the outcome measures were compared between treatments using Students paired t-tests. Analysis revealed significantly greater HR acceleration with CYL (24.7 bpm) than after WBV (15.8 bpm). The increase of sit-and-reach scores after WBV (4.7 cm) was statistically greater (p < 0.05) than after CYL (0.8 cm). After WBV, increases in peak and average isokinetic torque of knee extension, 7.7% and 9.6%, were statistically greater than after CYL (p < 0.05). Average torque of knee flexion also increased more with WBV (+7.8%) than with CYL (−1.5%) (p < 0.05). The findings of this study indicate that short-term WBV standing elicits acute enhancements of lower-extremity muscular torque and flexibility, suggesting the application of this technology as a preparatory activity before more intense exercise.

Evaluation of a training program for persons with SCI paraplegia using the Parastep 1 ambulation system: part 1. Ambulation performance and anthropometric measures.

OBJECTIVE To describe performance parameters and effects on anthropometric measures in spinal cord injured subjects training with the Parastep 1 system. DESIGN Before-after trial. SETTING Human spinal cord injury applied research laboratory. PARTICIPANTS Thirteen men and 3 women with thoracic (T4-T11) motor-complete spinal cord injury: mean age, 28.8yrs; mean duration postinjury, 3.8yrs. INTERVENTION Thirty-two functional neuromuscular stimulation ambulation training sessions using a commercially available system (Parastep-1). The hybrid system consists of a microprocessor-controlled stimulator and a modified walking frame with finger-operated switches that permit the user to control the stimulation parameters and activate the stepping. OUTCOME MEASURES Distance walked, time spent standing and walking, pace, circumferential (shoulders, chest, abdomen, waist, hips, upper arm, thigh, and calf) and skinfold (chest, triceps, axilla, subscapular, supraillium, abdomen, and thigh) measurements, body weight, thigh cross-sectional area, and calculated lean tissue. RESULTS Statistically significant changes in distance, time standing and walking, and pace were found. Increases in thigh and calf girth, thigh cross-sectional area, and calculated lean tissue, as well as a decrease in thigh skinfold measure, were all statistically significant. CONCLUSIONS The Parastep 1 system enables persons with thoracic-level spinal cord injuries to stand and ambulate short distances but with a high degree of performance variability across individuals. The factors that influence this variability have not been completely identified.

Evaluation of a training program for persons with SCI paraplegia using the Parastep®1 ambulation system: Part 5. Lower extremity blood flow and hyperemic responses to occlusion are augmented by ambulation training

OBJECTIVE To test whether 12 weeks of exercise conditioning using functional neuromuscular stimulation (FNS) ambulation alters the resting lower extremity blood flow and hyperemic responses to vascular occlusion in subjects with paraplegia, and to determine whether an association exists between limb flow and lower extremity fat-free mass. DESIGN Pretest, posttest. SETTING Academic medical center. PARTICIPANTS Subjects with chronic neurologically complete paraplegia. INTERVENTION Thirty-two sessions of microprocessor-controlled ambulation using electrically stimulated contractions of lower extremity muscles and a rolling walker. OUTCOME MEASURES Subjects underwent quantitative Doppler ultrasound examination of the common femoral artery (CFA) before and after training. End-diastolic arterial images and arterial flow-velocity profiles obtained at rest and after 5 minutes of suprasystolic thigh occlusion were computer-digitized for analysis of heart rate (HR), CFA peak systolic velocity (PSV), CFA cross-sectional area (CSA), flow velocity integral (FVI), pulse volume (PV), and CFA (arterial) inflow volume (AIV). RESULTS Significant effects of training on CSA (p < .0001), FVI (p < .05), computed PV (p < .001), and computed AIV (p < .01) were observed. Resting HR was lower following training (p < .05). The change for resting PSV approached but did not reach significance (p = .083). Analysis of postocclusion PV and AIV showed significant effects for conditioning status (p values < .01), postcompression time (p values < .0001), and their interaction (p values < .01). At 1 minute after occlusion, the posttraining AIV response was 78.2% greater in absolute magnitude and 17.4% more robust when expressed as a percentage change from its resting value than before training. Significant correlations were found between thigh fat free mass and both AIV and PV (p values < .05). CONCLUSION Exercise training using FNS ambulation increases the resting lower extremity AIV in individuals with paraplegia and augments the hyperemic response to vascular occlusion. Improved posttraining blood flow is attributable both to vascular structural changes and upregulation of vascular flow control mechanisms. Limb mass is associated with the volume of arterial blood flow.

The Acute Effects of Different Durations of Static Stretching on Dynamic Balance Performance

Costa, PB, Graves, BS, Whitehurst, M, and Jacobs, PL. The acute effects of different durations of static stretching on dynamic balance performance. J Strength Cond Res 23(1): 141-147, 2009-The purpose of this study was to examine the effects of different durations of static stretching on dynamic balance. Women (N = 28) were tested before and after 2 stretching interventions and a control condition on 3 separate days, at least 48 hours apart. The stretching sessions involved a cycle ergometer warm-up at 70 rpm and 70 W followed by passive stretching of the lower-body muscles. Each stretching position was held at a point of mild discomfort and repeated 3 times with 15 seconds between stretches. In the 2 stretching protocols, the positions were maintained for 15 or 45 seconds. The control condition involved the same cycle ergometer warm-up, with a 26-minute rest period between pre- and posttests. Balance was assessed using the Biodex Balance System. A 2-way repeated-measures analysis of variance was used with the effects of study condition (control, 15 seconds, 45 seconds) and time (pre-, postscores). Post hoc paired t-tests were used when appropriate to determine possible statistical significance between pre- and posttest scores. Analyses indicated no significant main effects for either study condition or time. However, there was a significant condition × time interaction (p < 0.05). Post hoc analyses indicated that the 15-second condition produced a significant improvement in the balance scores (p < 0.01), with no significant effects with the control condition or the 45-second treatment. The results of this study reveal that a stretching protocol of 45-second hold durations does not adversely affect balance when using the current stabilometry testing procedure. Furthermore, a stretching intervention with 15-second hold durations may improve balance performance by decreasing postural instability. Strength and conditioning professionals concerned with reported performance limitations associated with static stretching should consider applying shorter-duration stretching protocols when aiming to improve balance performance.

Modes, benefits, and risks of voluntary and electrically induced exercise in persons with spinal cord injury

Abstract Background: Sedentary lifestyles and physical deconditioning are commonly reported among persons with spinal cordinjury (SCI) ,although many forms of exercise have been shown to be beneficial. For individuals unable to perform voluntary exercise, involuntaryexercise by electrically stimulated contractions has been used to train individual body segments, invoke cycling movementswith or without arm propulsion, and stimulate ambulation. Objective: To evaluate the benefits and risks associated with various modes of exercise in persons with SCI. Methods: Literature review. Findings: Electrical stimulation of local muscle sites increases muscle mass and circulation and favorably alters muscle fiber composition.Electrically stimulated cycling has been observed to improve fitness, lower-extremity circulation and circulatory response to ischemia andto reverse cardiac muscle atrophy in persons with tetraplegia. Electrically stimulated ambulation improves upper-extremity endurance,lower-extremity circulation, and perception of body image. Studies of arm and wheelchair ergometry show increased arm endurance anddecreased cardiovascular risks associated with hyperlipidemia, while resistance training of the upper extremities improves strength andendurance. Because autonomic hyperreflexia, orthostatic intolerance, thermal dysregulation, and fracture are associated with exercise in SCI, risk reduction strategies and prompt intervention are required. Conclusions: Well-designed programs of exercise are beneficial for persons with tetraplegia and paraplegia. Risks an benefits varywith level of injury. Programs need to address prevention of and intervention for potential adverse effect associated with exercise in individuals with spinal cord dysfunction.

Metabolic and cardiac responses to robotic-assisted locomotion in motor-complete tetraplegia: a case report.

Abstract Background/Objective: To examine acute metabolic responses to treadmill locomotion in a participant with motor—complete tetraplegia. Methods: The participant—a woman with a chronic ASIA B C3–C4 spinal cor injury—walked on a treadmill with 40% body weight support (BWS) and robotic assistance. Oxygen consumption (VO2), minute ventilation (VE),and heart rate (HR) were measured during seated resting, supported standing, and 40 minutes of walking with stepping assistance from a Lokomat-driven gait orthosis. Results: A resting VO2 equal to 50 milliliters perminutewas predictably low, and did not change after the participant assumed an upright posture. Both VO2 and V2E increased immediately upon onset of locomotion, suggesting a neuragenie rather than a humoral regulatory response to movement. VO2 averaged 2.4 metabolic units (METS) during locomotion at an average expenditure of 2.98 kilocalories per minute. HR was unaltered by standing, but du ring locomotion averaged 1 7 beats higherthan du ring resting.lncreases in V E but not vo2 upon standing, and decreases in vo2 but not V E immediately after walking, rule out changes in V2E alone as the source for increased vo2 du ring walking. Conclusion: The data collected on this single participant show that treadmilllocomotion with BWS and robotic assistance elicits a metabolic response to treadmill gaiting characterized by increased VO2 , VE HR, and caloric expenditure