Arm Cycle Ergometry (ACE) Training

Arm cycle ergometry (ACE) is a mode of rhythmic exercise where the arms are used to spin an axle-and-crank system that is similar to a stationary bicycle but for upper extremity use. Usually, the exerciser remains in their chair, with the ergometer placed on a table. Another approach is to fix the ergometers to a wall or other vertical structure. If an ergometer is intended to be used by more than one person, it is important that the height of the device is adjustable to accommodate different statures and wheelchairs (and thus different heights of the apex of the shoulders). These ergometers are most often used to achieve sustained, endurance-type exercise targeting increases in VO2 and HR. However, testing and training of muscular power production can also be achieved via sprint-type cycling. Arm ergometers can be simple to construct and thus, in theory, should be relatively inexpensive and accessible. They are general conditioning tools, but their transferability to real-world tasks is somewhat limited. Furthermore, it is generally thought that the movement pattern is sub-optimal for the upper extremities and thus there could be an increased risk for overuse injuries using this mode of exercise. Other rhythmic upper-extremity exercise devices have been developed to address this concern, such as the Vitaglide. Despite these shortcomings, arm ergometry is a commonly employed mode of exercise due to the simplicity of the equipment and the predictability of the physiological response.

Author Year

Country
Research Design

Score
Total Sample Size

Methods

Outcome

Graham et al. (2019)

USA

RCT

PEDro=5

NInitial=9, NFinal=7

Population: Gender: males=6, females=1; Mean time since injury: >3 yr. Intervention group: Mean age: 49.4±13yr; Level of injury: C6=1, C8=1, T8=1, L1=1; Level of severity: AIS A=1, B=3. Control group: Mean age: 51.3±1.2yr; Level of injury: C7=1, T6=1, T8=1, T12-L1=1; Level of severity: AIS A=1, B=1, D=1.

Intervention: Subjects were randomly allocated to either the intervention group or the control group. The intervention group participated in 6 wk high-intensity interval training (HIIT), whereas the control group performed moderate-intensity training (MIT). Both groups performed training on an arm ergometer. The intervention group trained for 20min, 2x/wk, whereas the control group trained for 30 min, 3x/wk. Both groups trained for 6wk. Assessments were taken at baseline, and post-intervention.

Outcome Measures: fat mass, lean mass, percent body fat, percent arm fat, percent leg fat, blood pressure, resting energy expenditure, oral glucose tolerance test, quantitative insulin sensitivity check index (QUICKI), blood lipids, strength assessment, peak oxygen uptake, peak power on ergometer.

·         No effect VO2peak

·         Time effect for QUICKI.

·         There was a significant effect of time on muscle strength in the chest press (0.035) and latissimus pulldowns (p=0.021) exercises. Additionally, there was a significant interaction effect for chest press in favour of MIT.

·         Almost all patients ↓ in total cholesterol and LDL, whereas changes in serum triglycerides and HDL were variable.

Kim et al. (2015)

Korea

RCT

PEDro=5

N=15

Population: 15 participants (9 males, 6 females) with SCI (ASIA-A &B, C5-T11). Mean age was 33 and all participants had SCI for more than 6 months. 8 participants allocated to the hand-bike exercise group, 7 participants to the control group.

Intervention: Participants exercised with the indoor-hand bike for 60min/day, 3 days/week, for 6 weeks under supervision of an exercise trainer. Participants maintained a heart rate of 70% of their maximum. Exercise intensity was gradually ↑ on a weekly basis using the Borg rating of perceived exertion (RPE level 5 to 7). The control group continued with usual activities.

Outcome Measures: Body mass index (BMI), waist circumference, percent body fat, insulin level, homeostasis model assessment of insulin resistance (HOMA-IR) level, upper body muscle strength (using a dynamometer), VO2peak, lipid metabolite indices (including cholesterol, triglycerides, high & low density lipoprotein cholesterol levels.

·         The exercise group ↑ in V02peak and upper body strength compared with the control group following intervention.

·         Post-intervention, the exercise group showed significant ↓ HOMA-IR levels compared with the control group.

·         The exercise group exhibited significantly lower insulin and HOMA-0R levels, and ↑ in high density lipoprotein cholesterol after the exercise training period compared with baseline levels.

·         No change in glucose, total cholesterol, triglycerides, or low density lipoprotein were observed in the exercise group.

Rosety-Rodriguez et al. (2014)

Spain

RCT

PEDro=7

N=17

Population: Experimental group: Mean age: 29.6±3.6yr; Time post injury: 54.8±3.4mo. Control group: Mean age: 30.2±3.8yr; Mean time since injury: 55.7±3.6mo. Gender: males=17, females=0; Level of injury: T2-L5=17.

Intervention: 12wk arm cranking exercise program for 3 sessions/wk. Each training session consisted of warm-up (10-15min), arm crank (20-30min; increasing 2min and 30sec every 3wk) at a moderate work intensity of 50% to 65% of heart rate reserve (starting at 50% and increasing 5% every 3wk), and cool-down (5-10min). Control participants completed assessments but did not take part in a training program. The control group consisted of individuals matched for age, sex, and injury level.

Outcome Measures:  Plasma levels of leptin, adiponectin, plasminogen activator inhibitor-1 (PAI-1), TNF-a, IL-6, maximum oxygen consumption [VO2peak], anthropometric index [AI], waist circumference [WC], and body mass index [BMI].

 

·         ↑ VO2peak in the intervention group (p=0.031).

·         Leptin, TNF-a and IL-6 levels were significantly ↑ in the exercise group (p<0.05) when compared to the control after the exercise intervention.

·         All other measures were not significantly different between the two groups (p>0.05)

Ordonez et al. (2013)

Italy

RCT

PEDro=8

N=17

Population: Intervention group (n=9): mean age: 29.6yr; Gender: males=9, females=0; mean time post injury: 54.8mo. Control group (n=8): mean age: 30.2yr; Gender: males=8, females=0; mean time post injury: 55.7mo; At or below the fifth thoracic level (T5).

Intervention: Intervention group performed a 12-week arm-cranking exercise program, 3 sessions/wk, consisting of warming-up (10-15min) followed by a main part in arm-crank (20-30min [increasing 2min and 30s every 3wk]) at a moderate work intensity of 50% to 65% of the HR reserve and by a cooling-down period.

Outcome Measures: Plasmid levels of total antioxidant status, erythrocyte glutathione peroxidase activity malondialdehyde and carbonyl group levels, physical fitness and body composition.

·         When compared with baseline results, VO2peak was significantly ↑ in the intervention group.

·         Both total antioxidant status and erythrocyte glutathione peroxidase activity were significantly ↑ at the end of the training program.

·         Plasmatic levels of malondialdehyde and carbonyl groups were significantly reduced following training.

Jacobs et al. (2009)

USA

RCT

PEDro=5

N=18

Population: Traumatic SCI: RT Group: Mean age: 33.7±8.0yr; Gender: males=6, females=3; Mean body mass: 72.3±18.3 kg: ET group: Mean age: 29.0±9.9yr; Gender: males=6, females=3; Mean body mass: 83.7±8.9kg.

Intervention: Subjects participated in a series of testing sessions before and after a 12wk training period. Patients were randomly assigned to two groups. The endurance training (ET) group performed 30 min of arm cranking exercise using a Saratoga arm crank device during each session at 70%–85% of HRpeak. The resistance training (RT) group performed three sets of 10 repetitions at six Hammer Strength MTS exercise stations (including horizontal press, horizontal row, overhead press, overhead pull, seated dips, and arm curls) with an intensity ranging from 60% to 70% of 1 repetition maximum (1RM).

Outcome Measures: VO2peak, Graded exercise test (GXT); assessed at baseline and at end of treatment (12 wks).

·         Significant effects of both modes of training (RT and ET) in the physiological responses to VO2peak GXT were observed.

·         Muscular strength significantly ↑ for all exercise maneuvers in the RT group with no changes detected in the ET group

·         VO2peak values were significantly greater after RT (15.1%) and ET (11.8%).

·         Both RT and ET study groups displayed significant ↑ in POpeak and POmean.

·         Mean power ↑ 8% and 5% for the RT and ET groups, respectively, with no statistically significant differences apparent between groups. RT produced significantly greater gains in POpeak (15.6%) compared with ET (2.6%).

·         The RT group displayed significantly ↑ strength values ranging from 34% to 55% for the six exercise maneuvers. In contrast, the ET group did not display ↑ in muscular strength for any of the six exercises after 12wk of training.

Brizuela et al. (2020)

Spain

Pre-Post

N=11

Population: Mean age: 36.5±10.0yr; Time since injury: 13.1±9.9yr; Injury etiology: traumatic SCI; Level of injury: C4-7; Level of severity: AIS A=8; AIS B=3.

Intervention: Individuals were divided into two groups: higher or lower CSCI. They underwent an 8wk stationary arm-crank exercise (ACE) training program twice/wk. Training was performed on a stationary and mechanically-braked pedaling machine, modified and converted to an adapted arm-crank machine.

Outcome Measures: Quadriplegia index of function (QIF) questionnaire, Fukuda Sangyo ST-250 spirometer, Borg CR10 scale.

·         ↑ POpeak in both groups (p<0.05), whereas maximum voluntary ventilation (MVV) and low frequency HRV (LF) improved only in the lower CSCI group (p<0.05).

·         QIF and POpeak were significantly correlated before (r=0.88; p<0.01) and after (r=0.86; p<0.01) the training period.

Williams et al. (2020)

Canada

Pre-Post

N=14

Population: Gender: males=8, females=6; mean age=44.3yr; level of injury: C4=1, C5=2, C6=1, C7=1, T4=2, T5=1, T8=1, T11=1, T12=2; level of severity: AIS A=6, B=5, C=2, D=1; time since injury ≥1yr.

Intervention: participants took part in a 5wk at 3 sessions/wk of arm crank ergometry (ACE) training protocol which featured modulations in cadence and resistance, as well as back supported and unsupported bouts.

Outcome Measures: Changes in aerobic capacity (peak oxygen consumption) and seated balance control (centre of pressure parameters).

·         ↑ VO2peak by an average of 16% following training (p=.005).

·         Unsupported ACE was effective for eliciting trunk muscle activity (p<0.05).

·         Static sitting balance significantly improved from pre to post intervention, but only when tested with eyes closed as a measure by a reduction in area (p=.047) and velocity of centre of pressure (p=.013).

·         No significant changes were observed in static sitting balance with eyes open, or in dynamic sitting balance.

Bresnahan et al. (2019)

USA

Pre-Post

NInitial=10, NFinal=6

Population: Age: 36.7±12.5yr; Gender: males=8, females=2; Level of injury: cervical=3, thoracic=7; Severity of injury: AIS A=8, AIS B=2; Mean time since injury: 12.4yr.

Intervention: Arm crank ergometry (ACE) 30 min/day, 3 days/wk for 10 days at 70% VO2peak.

Outcome Measures: VO2, respiratory quotient (RQ), graded exercise testing (GXT) time, peak power, heart rate, energy expenditure (EE), time to traverse a 100ft-5° ramp, 12-min wheelchair propulsion test, body composition (% fat mass; bone mineral content; bone mineral density; fat mass; lean body mass), metabolic profile (%Beta cell activity; %insulin sensitivity; high-density lipoprotein-cholesterol; HOMA: homeostasis modeal assessment (HOMA); Insulin sensitivity index; low-density lipoprotein-cholesterol; triglycerides; fasting glucose to insulin ratio).

·         Post intervention there was significant improvement in resting VO2 (p=0.046), VO2peak (p=0.028), POpeak (p=0.026), RQ (p=0.028), and 12-min wheelchair propulsion test (p=0.028).

·         There was no significant improvement post intervention in GXT time, HRpeak, EE, and time to traverse a 100ft-5° ramp.

·         There was no significant difference in any body composition or lipid profile measures post-intervention.

·         Fasting insulin (p=0.028), fasting glucose to insulin (p=0.028), and HOMA %insulin sensitivity (p=0.046) which improved.

Horiuchi & Okita, (2017)
Japan
Pre-Post
N=9
Population: Mean age: 38±10yr; Gender: males=9, females=0; Level of injury: T8-L1=9; Level of severity: AIS A=7, AIS B=2; Mean time since injury: 16±7.1yr.
Intervention: Individuals with a SCI) performed 2 × 30min sets of arm-cranking exercises with a 10 min resting interval between them, 4 days/wk for 10 wk at an intensity of 50~70% heart rate reserve (HRR).
Outcome Measures: Isometricmaximum handgrip (HG), strength, body mass (BM), waist circumference (WC), aerobic capacity (VO2 peak), plasminogen activator inhibitor 1 (PAI-1), systolic blood pressure (SBP), glucose metabolism, and lipid profiles (triglycerides (TG), high-density lipoprotein (HDL) cholesterol).

·         ↑ VO2peak with the 10-week arm-cranking exercise training (p<0.05).

·         After the 10-week detraining phase, WC, BM, VO2peak, SBP, TG, and PAI-1 accurately recovered with statistical differences between post-training and detraining (p<0.05).

·         Spearman rank order analysis revealed that changes in PAI-1 were related to changes in VO2peak, BM, WC, TG, and HDL cholesterol.

·         Multiple linear regression analysis revealed that WC was the most sensitive factor for predicting changes in PAI-1 (p=0.038).

Valent et al. (2010)

Netherlands

Longitudinal cohort study

N=20

 

Population: Experimental Group (n=17): Mean age=46yr; Gender: male=13, female=4; Level of injury: 10=paraplegia, 7=tetraplegia; Control Group (n=17): Mean age= 40yr; Gender: male=13, females=4; Level of injury:11=paraplegia, 6=tetraplegia.

Intervention: Experimental subjects received hand cycle training in addition to regular care and the control subjects only received regular care. Individuals with paraplegia started the hand cycle training programme at the start of active rehabilitation and those with tetraplegia started 3 months later. Both continued training twice/wk until discharge. The duration of training sessions was between 35 and 45 min. The pre- and post-test outcomes of the experimental subjects were compared with the pre- and post-test outcomes of the matched control subjects.

Outcome measures: peak power output (POpeak), peak oxygen uptake (V02peak), oxygen pulse, isometric peak muscle strength of the upper extremities, pulmonary function.

·         No significant effect of hand cycle training was found for V02peak. After correction for body mass, again a trend (p=0.070) was found for POpeak (W/kg), but no effect was found on V02peak (ml/min/kg).

·         Although no significant effect of hand cycle training was found for the training versus control group on the outcome measures of wheelchair capacity, positive trends were found for wheelchair POpeak and oxygen pulse with p-values of 0.079 and 0.052, respectively

·         Significantly larger improvements were found in the experimental group compared to the control group for muscle strength of elbow flexion (only left), internal and external rotators of the shoulder (both left and right). No training effect was found for the other muscle groups.

·         No significant training effects of hand cycling were found for pulmonary function.

·         Comparing pre- with post-test results in the training group only, there were substantial improvements in POpeak (p<0.001), but only a trend for improvement in V02peak (p=0.065).

Valent et al. (2009)

Netherlands

Pre-Post

N=22

Population: Mean age: 39yr.; Gender: males=18, females=4; Level of injury: C5-T1=22; Mean time post injury: 10yr.

Intervention: Participants completed a total of 24 sessions of hand cycle interval training program within a continuous period of 8-12wk. The duration of one training session was between 35-45min. During training, participants wore heart rate monitors and were expected to train at 60% to 80% of heart rate reserve (HRR). Rating of perceived exertion (RPE) was monitored using the Borg 10-point scale and was intended to range from 4 to 7.

Outcome measures: peak power output (POpeak), peak oxygen uptake (V02peak), peak muscle strength (force-generating capacity) of the upper extremities, respiratory function, participant-reported shoulder pain.

·         The VO2peak significantly improved, on average, 114 mL*min1 (SD=204) after training, which was an ↑ of 8.7% (SD=13.9%). In addition, a significant improvement in POpeak of 8.3 W (SD=5.8) was found after training, which was an ↑ of 20.2% (SD=15.0%).

·         Mean peak respiratory exchange ratio was 1.10 in both the pre-test and the post-test, suggesting that, in general, V02peak was reached.

·         No significant improvement in O2P (mean difference=1.3 mL*beat1, SD=0.2) (p=.06) was seen in the pretraining-post training comparison. As expected, HRpeak did not change between pretraining (X=128 b*min1, SD=24) and post training (127 b*min1, SD=27). A significant ↓ in V02submax during hand cycling of 73 mL*min1 (SD=122) (X=8.8%, SD=14.6%) (p=.04) was found at a constant power output, indicating improved gross mechanical efficiency during hand cycling.

·         Only shoulder abduction strength significantly improved (X=5.6%, SD=11%).

·         No effects of hand cycle training were found on pulmonary function outcome measures.

El-Sayed et al. (2005)

UK

Pre-Post

N=12

Population: 5 SCI, lesion below T10, age 32yr; 7 AB controls, age 31yr.

Intervention: Arm ergometry, 30 min/d (60%–65%VO2peak), 3 d/wk, 12 wks.

Outcome Measures: VO2peak, HRpeak, workload, total cholesterol (TC), triglycerides, HDL.

·         (Results repeated from 2004 paper)

·         Training improved HDL but did not alter TC or triglycerides.

El-Sayed et al. (2004)

United Kingdom

Pre-Post

N=12 (N=5 SCI)

Population: SCI Group: Mean age: 32.0±1.6yr; Gender: males=5, females=0; Level of injury: Able-Bodied Group: Mean age: 31.0±2.9yr.

Intervention: Arm ergometry, 30 min/day (60%– 65%VO2peak), 3 days/wk, 12wk.

Outcome Measures: Oxygen consumption (VO2peak), heart rate (HRpeak), work load (WLpeak), platelet aggregation.

·         ↑ VO2peak, lower heart rate, and greater work load among normal subjects compared to those with SCI (p<0.05 for all).

·         There were no significant differences in platelet aggregation post intervention for either group, or between groups.

Silva et al. (1998)

Brazil

Pre-Post

N=24

Population: N=24 participants (12 people with paraplegia, 12 able-bodied individuals), median age SCI: 31yr (range 22-54), control: 30 (range 22-52), T1-T12, all ASIA A, >3yr after injury.

Intervention: Arm cranking aerobic training: 30 mins, 3x/wk x 6 wks.

Outcome measures: Spirometry.

·         After aerobic training, SCI participants showed significant ↑ in FVC and the ventilatory muscle endurance, so that peak voluntary ventilation at 70% time values post-training were not different from the initial values of able bodied individuals.

·         Severely limited ventilatory muscle endurance in people with paraplegia can be improved by arm cranking.

DiCarlo et al. (1988)

USA

Pre-Post

N=4

Population: Mean age: 24.3yr; Gender: males=4; Injury etiology: traumatic SCI=3, congenital SCI=1; Level of injury: C5-7=3, T7-8=1.

Intervention: Individuals completed pre and post training maximal exercise testing, which consisted of noncontinuous, multistage graded arm ergometry. Training sessions were 30min ACE, 3 times/wk for 5wk at an intensity of 60-80% of HRpeak. Heart rates, maximal work loads and oxygen consumption (VO2peak) were measured.

Outcome Measures: Daniel’s one-way respiratory valve, Parkinson-Cowan Dry Gas Meter, Beckman E2 Oxygen Gas Analyzer, Goddart KK Capnograph, Modified V5 chest lead, Hewlett Packard oscilloscope.

·         VO2peak significantly ↑ from pretraining to post training (p<0.05).

·         Maximal work loads did not ↑ significantly from pretraining to post training (p>0.05).

McLeod et al. (2020)
Canada
RCTPEDro=6
N=20

Population: MICT Group (n=10): Mean age=45yr; Gender: males=5, females=5; Level of injury: C2-C7, T8-L4; Mean time post injury=56 days; SIT Group (n=10): Mean age= 47yr.; Gender: male=10, female=0; Level of injury: C2-C4, T7-L2; Mean time post injury=72 days.

Intervention: Participants were randomized to SIT or moderate-intensity continuous training (MICT). SIT consisted of 3 × 20 sec ‘all-out’ (>100% peak power output) arm-cycle sprints interspersed with 2 mins of active recovery (10% peak power output; total time commitment, 10 mins). MICT involved 20 mins of arm-cycling (45% peak power output; total time commitment, 25 mins). Both training interventions were delivered 3 times/wk for 5wk. peak power output, sub-maximal exercise performance and exercise self-efficacy were assessed at baseline (pre-training) and 72 h following the final training session (post-training).

Outcome measures: Heart rate (HR), Borg’s Rating of Perceived Exertion (RPE), peak power output (POpeak), maximal and sub-maximal power outputs, exercise enjoyment, exercise self-efficacy, and pain.

·         POpeak ↑ by 39% (95% CI: 18, 60) for SIT, and 33% (95% CI: 15, 50) for MICT, with no significant difference between groups (mean group difference: 6%; 95% CI: −19, 31; p=0.524).

·         Exercise workload during the SIT and MICT corresponded to 154%, and 64% of POpeak achieved at pre-training, respectively. Over the course of the 5 weeks of training, the average volume of exercise performed during SIT was lower than MICT (13 ± 8 kJ vs 37 ± 16 kJ).

·         Improvements in POpeak were not different across persons with paraplegia or tetraplegia.

·         Compared to the MICT group, mean HR, central RPE, and peripheral RPE were significantly (P<0.05) higher for the SIT group across exercise sessions.

·         There were no between-group differences in power output achieved across a range of submaximal workloads.

·         There were no between-group differences in exercise enjoyment, changes in exercise self-efficacy, and pain.

Nightingale et al. (2017)
U.K.
RCT
PEDro=5
NInitial=24,NFinal=21
Population: Control Group (n=8): Mean age: 48±10yr; Gender: males=6, females=2; Level of injury: T4–L3 (≤T6=4, ≥T6 =4); Level of severity: AIS A-B=7, AIS C-D=1; Mean time since injury: 20±10yr; Intervention Group (n=13): Mean age: 46±6yr; Gender: males=9, females=4; Level of injury: T4–L1 (≤T6=4, ≥T6=4; Level of severity: AIS A-B=11, AIS C-D=2; Mean time since injury: 14±11yr
Intervention: Participants were randomized into either a 6wk prescribed home-based exercise intervention (INT) or control group (CON). Participants allocated to the exercise group completed four, 45 min moderate-intensity (60-65% VO2peak oxygen uptake (VO2peak) arm-crank exercise sessions/wk.
Outcome Measures: Physical activity energy expenditure, Body composition, Metabolic regulation, VO2peak, power output, Homeostasis Model Assessment of Insulin Resistance (HOMA2-IR), Fasting and postprandial concentrations of plasma glucose and serum insulin.

·         The INT group significantly ↑ (p<0.001) VO2peak and POpeak, whereas these outcomes remained unchanged in the CON group.

·         The moderate-intensity upper-body exercise INT group significantly ↑ physical activity energy expenditure and minutes spent performing moderate-to-vigorous intensity physical activity relative to the CON group (p<0.01).

·         Changes in fasting serum insulin concentrations and HOMA2-IR were different between the two groups (p<0.044). The INT group significantly ↓ fasting serum insulin concentrations and HOMA2-IR (p<0.035), whereas these outcomes were unchanged in the CON group.

·         Fasting plasma glucose and outcomes derived following an oral glucose tolerance test (post-load responses indicative of peripheral insulin resistance) were not significantly different over time (all P >0.6), with no interaction effects (all P >0.3)

de Groot et al. (2003)

Netherlands

RCT

PEDro=7

N=6

Population: 4 male, 2 female, C5-L1, AIS A (n = 1), B (n = 1), and C (n = 4), age 36yr, 116 d post-injury.

Intervention: Randomized to ACE low-intensity (LI: 40%–50% HRR) or high-intensity (HI: 70%–80% HRR) arm ergometry. The 1 h interval training consisted of 3 min exercise bouts interspersed with 2 min of rest 3 d/wk, 8wk.

Outcome Measures: VO2peak, peak power output, insulin sensitivity (HOMA-CIGMA test), blood glucose and lipid profile (total cholesterol, high-density lipoprotein cholesterol, high-density lipoprotein cholesterol and triglycerides).

·         ↑ in VO2peak and POpeak for the group as a whole (P<0.05).

·         VO2peak ↑ significantly more, and triglycerides and TC/HDL ratio ↓ significantly more in the HI group than in the LI group (P=0.05).

·         There was a significant difference in insulin sensitivity between groups (P = 0.05), with a non-significant decline in the HI group and a nonsignificant improvement in the LI group with training.

·         The ↑ in POpeak and the changes in lipid profile parameters TC, HDL and LDL did not differ between the two groups.

·         A positive correlation was observed between VO2peak and insulin sensitivity (r = 0.68, p = 0.02).

Discussion

There is strong, level 1a evidence, from three RCT studies showing that arm cycle ergometry (ACE) training, 3 sessions per week for 8-12 weeks results in increased cardiorespiratory fitness (as assessed by peak rate of whole-body oxygen consumption during exercise). Further moderate evidence, two level 1b RCTs, and weak evidence, from five pre/post studies, corroborate the beneficial effect of ACE on cardiorespiratory fitness with 2 to 4 sessions per week for as little as 2 to as many as 16 weeks. In fact, only two of the 18 studies included in the above table suggest no effect of ACE on cardiorespiratory fitness. There is also solid evidence for benefit of ACE on endurance. There are two level 1a RCTs, two level 1b RCTs, and three level 4 pre/post studies providing evidence that ACE can benefit a component on endurance performance in people with SCI. This robust evidence-base for the effect of ACE training on cardiorespiratory fitness and endurance is well established, and is a large part of the foundation of the existing SCI physical activity guidelines mentioned in the introduction.

Conclusions

Ordonez et al (Ordonez et al. 2013) provided Level 1 evidence that 12 wk of 3 day/wk of ~45 min benefits VO2peak.

Rosety-Rodriqguqez et al (Rosety-Rodriguez et al. 2014) provided Level 1 evidence that 12 wk of 3 day/wk of ~45 min ACE benefits VO2peak.

McLeod et al (McLeod et al. 2020) provided Level 1 evidence that 5 wk of 2 day/wk of ACE benefits VO2peak.

Nightingale et al (Nightingale et al. 2017) provided Level 2 evidence that 6 wk of 3 day/wk of ACE benefits VO2peak and POpeak.

Graham et al (Graham et al. 2019) provided Level 2 evidence that 6 wk of 2 day/wk of on ACE benefits strength.

Kim et al (Kim et al. 2015) provided Level 2 evidence that 6 wk of 3 day/wk of 60 min ACE increases VO2peak and strength.

Jacobs et al (Jacobs 2009) provided Level 2 evidence that 12 wk of 2 day/wk of 20 min ACE benefits VO2peak and POpeak.

Brizuela et al (Brizuela et al. 2020) provided Level 4 evidence that 8 wk of 2 day/wk of ACE benefit POpeak.

Williams et al (Williams et al. 2020) provided Level 4 evidence that 5 wk of 3 day/wk of ACE benefits VO2peak.

Bresnahan et al (Bresnahan et al. 2019) provided Level 4 evidence that 2 wk of 3 day/wk of ACE benefits VO2peak and POpeak.

Horiuchi et al (Horiuchi & Okita 2017) provided Level 4 evidence that 10 wk of 4 day/wk of ACE benefits VO2peak.

Valent et al (Valent et al. 2010; Valent et al. 2009) provided Level 4 evidence that 8-12 wk of 2 day/wk of ACE benefits VO2peak, POpeak, and some measures of strength.

El-Sayed et al (El-Sayed 2004; El-Sayed & Younesian 2005) provided Level 4 evidence that 12 wk of 3 day/wk of ACE benefits VO2peak.

Silva provided is Level 4 evidence that 6 wk of 3 day/wk of ACE benefits pulmonary function.

DiCarlo et al (DiCarlo 1988) provided Level 4 evidence that 5 wk of 3 day/wk of ACE benefits VO2peak.

De Groot et al (De Groot et al. 2003) provided Level 4 evidence that 8 wk of 3 day/wk of ACE benefits VO2peak and POpeak.