A SYSTEMATIC REVIEW AND META-ANALYSIS COMPARING CARDIOPULMONARY EXERCISE TEST VALUES OBTAINED FROM THE ARM CYCLE AND THE LEG CYCLE RESPECTIVELY IN HEALTHY ADULTS

. 2016 Dec;11(7):1006–1039.

Detailed characteristics of included studies

Aminoff, T. et al. (1996)
Title	Physical work capacity in dynamic exercise?with differing muscle masses in healthy young and older men
Methods	Cross-sectional
Participant status	19 healthy, non-smokers, and physically active men. Subjects participated in conditioning exercises, on average, two to four times a week. Group ”old”: n = 9 Group ”young”: n = 10 Age: ”old” 56.9 ± 1.5 years, ”young” 26.3 ± 2.3 years Gender (M/F): Only males Height: ”old”: 178 ± 6.1 cm, ”young” 184.2 ± 4.8 cm Bodyweight: ”old”: 82.8 ± 7.2 kg, ”young” 81.7 ± 11.1 kg BMI: ”old” 26.2 ± 3.1 kg/m², ”young” 26.3 ± 2.3 kg/m² AC RER: ”old” 1.15 ± 0.04, ”young” 1.15 ± 0.08 LC RER: ”old” 1.09 ± 0.04, ”young” 1.13 ± 0.05
Study protocol
	AC or LC tested first: Random Time between tests: 1 day AC Start Watt: not reported LC Start Watt: not reported AC Watt increase/min: 5.35 W/min LC Watt increase: 10.7 W/min
Outcomes of interest	VO2_max and RER
Risk of bias	SumQAT: 4
Notes
Aminoff, T. et al. (1999)
Title	Physiological strain during kitchen work in relation to maximal and task-specific peak values
Methods	Cross-sectional
Participant status	Nine kitchen workers from a large hospital kitchen with a conveyor belt, collecting and sorting dirty plates. Group ”female”: n = 6 Group ”male”: n = 3 Age: ”female” 32.3 ± 10.3 years, ” male” 28.7 ± 8.6 years Gender (M/F): “female”: only females, “male”: only males Height: ” female”: 171.8 ± 7.2 cm, ” male” 179.4 ± 5.4 cm Bodyweight: ” female”: 62.9 ± 6.1 kg, ” male” 75.1 ± 5.9 kg BMI: ” female” 21.3 ± 1.7 kg/m², ” male” 23.4 ± 3.1 kg/m² AC RER: ” female” 1.10,” male” 1.12 LC RER: ” female” 1.10 ” male” 1.12
Study protocol
	AC or LC tested first: LC Time between tests: 1 day AC Start Watt: not reported LC Start Watt: not reported AC Watt increase/min: 5.5 W/min LC Watt increase: “25 or 50” Watts every third minute
Outcomes of interest	VO2_max and RER
Risk of bias	SumQAT: 5
Notes
Bhambhani, Y, et al, (1998)
Title	Muscle oxygenation during incremental arm and leg exercise in men and women
Methods	Cross-sectional
Participant status	Fifteen men and 10 women who were free from metabolic and cardiorespiratory diseases. The volunteers were university students and members of local sports club. Group ”female”: n = 10 Group ”male”: n = 15 Age: ”female” 27.3 ± 4.9 years, ” male” 25.2 ± 5.3years Gender (M/F): “female”: only females, “male”: only males Height: ” female”: 166 ± 4.1 cm, ” male” 176 ± 8.0 cm Bodyweight: ” female”: 64.5 ± 5.4 kg, ” male” 72.8 ± 8.5 kg BMI: ” female” 22.1 ± 3.9 kg/m², ” male” 24.8 ± 2.1 kg/m² AC RER: ” female” 1.21 ± 0.08 ” male” 1.2 ± 0.09 LC RER: ” female” 1.2 ± 0.08 ” male” 1.19 ± 0.07
Study protocol
	AC or LC tested first: Random Time between tests: Within one week AC Start Watt: 25 LC Start Watt: 30 AC Watt increase/min: 12.5 W/min LC Watt increase: 15 W/min
Outcomes of interest	VO2_max and RER
Risk of bias	SumQAT: 5
Notes
Bhambhani, Y, et al, (1995)
Title	Prediction of stroke volume during upper and lower body exercise in men and women
Methods	Cross-sectional
Participant status	37 recreationally active subjects not involved in any particular exercise-training programme. Group ”female”: n = 12 Group ”male”: n = 25 Age: ”female” 32.1 ± 7.7 years, ” male” 35.0 ± 7.3 years Gender (M/F): “female”: only females, “male”: only males Height: ” female”: 161.1 ± 8.1 cm, ” male” 177.8 ± 6.6 cm Bodyweight: ” female”: 59.5 ± 6.0 kg, ” male” 82.9 ± 9.1 kg BMI: ” female” 22.9 kg/m², ” male” 26.2 kg/m² AC RER: ” female” 1.31 ± 0.11 ” male” 1.2 ± 0.09 LC RER: ” female” 1.33 ± 0.07 ” male” 1.22 ± 0.06
Study protocol
	AC or LC tested first: Random Time between tests: Within two weeks AC Start Watt: 12.5 LC Start Watt: 30 AC Watt increase/min: 6.25 W/min LC Watt increase: 15 W/min
Outcomes of interest	VO2_max and RER
Risk of bias	SumQAT: 5
Notes
Bhambhani, Y, et al, (1991)
Title	Transfer effects of endurance training with the arms and legs
Methods	RCT
Participant status	16 healthy middle-aged male subjects in the arm group, and 8 healthy middle-aged male subjects in the leg group. Group ”arm”: n = 16 Group ”leg”: n = 8 Age: ” arm” 35.2 ± 6.6 years, ” leg” 41.0 ± 4.7 years Gender (M/F): “arm” only males, “leg” only males Height: ” arm”: 176 ± 7.1 cm, ” leg” 177.6 ± 5.0 cm Bodyweight: ” arm”: 85.5 ± 9.9 kg, ” leg” 80.4 ± 11.1 kg BMI: ” arm” 27.6 kg/m², ” leg” 25.49 kg/m² AC RER: ” arm” 1.15 ± 0.05 ” leg” 1.21 ± 0.09 LC RER: ” arm” 1.21 ± 0.03 ” leg” 1.21 ± 0.07
Study protocol
	AC or LC tested first: Random Time between tests: Within two weeks AC Start Watt: 12.5 LC Start Watt: 30 AC Watt increase/min: 6.25 W/min LC Watt increase: 15 W/min
Outcomes of interest	VO2_max and RER
Risk of bias	SumQAT: 4
Notes
Barstow, T. J. et al. (1993)
Title	O₂ uptake kinetics and the O₂ deficit as related to exercise intensity and blood lactate
Methods	Cross-sectional
Participant status	Four untrained subjects aged 24-38 years, weight 59-89 kg n = 4 Age: 24-38 years Gender (M/F): Three males and one female Height: ” arm”: 176 ± 7.1 cm, ” leg” 177.6 ± 5.0 cm Bodyweight: 59-89 kg
Study protocol
	AC or LC tested first: Cannot determine (CD) Time between tests: not reported AC Start Watt: Not reported LC Start Watt: Not reported AC Watt increase/min: Not reported LC Watt increase: Not reported
Outcomes of interest	VO2_max
Risk of bias	SumQAT: 3
Notes
Boileau, R. A. et al. (1984)
Title	Cardiovascular and metaboli contributions to the maximal power of the arms and legs
Methods	Cross-sectional
Participant status	Moderately active, nonathletic male college students. n = 40 Age: 18-25 years Gender (M/F): only males Bodyweight: 75.8 ± 7.8 kg AC RER: 1.16 ± 0.08 LC RER: 1.16 ± 0.08
Study protocol
	AC or LC tested first: Random Time between tests: Cannot determine AC Start Watt: 60 LC Start Watt: 150 AC Watt increase/min: 6 LC Watt increase: 15
Outcomes of interest	VO2_max and RER
Risk of bias	SumQAT: 6
Notes
Bond, V. et al. (1986)
Titel	Aerobic capacity during two-arm and one-leg exercise
Methods	Cross-sectional
Participant status	Eight healthy males. The subjects had not participated in any upper or lower body conditioning for 12 months prior to the tests n = 8 Age: 24 ± 4.7 years Gender (M/F): only males Height: 177 ± 6.5 cm Bodyweight: 77 ± 9.8 kg BMI: 24.58 kg/m²
Study protocol
	AC or LC tested first: Random Time between tests: Within one weeks AC Start Watt: 30 LC Start Watt: 30 AC Watt increase/min: 30 W/min LC Watt increase: 30 W/min
Outcomes of interest	VO2_max and RER
Risk of bias	SumQAT: 4
Notes
Bouchard, C. et al. (1979)
Title	Specificity of maximal aerobic power
Methods	Cross-sectional
Participant status	30 moderately active male subjects. n = 30 Age: 28 ± 4.5 years Gender (M/F): only males Bodyweight: 73.0 ± 6.6
Study protocol
	AC or LC tested first: Random Time between tests: Within two weeks AC Start Watt: 75 LC Start Watt: 125 AC Watt increase/min: 10 W/min LC Watt increase: 25 W/min
Outcomes of interest	VO2_max
Risk of bias	SumQAT: 5
Notes	The study reports a correlation coefficient between AC and LC on r = 0.70.
Castro, R. et al. (2011)
Title	Different ventilatory responses to progressive maximal exercise test performed with either the arms or legs
Methods	Cross-sectional
Participant status	12 subjects of hospital staff and university students. They were considered healthy upon a clinical evaluation (physical examination and clinical history) and a maximal exercise test performed on a cycle ergometer. None of the subjects were engaged in regular physical exercise. None of the subjects were accustomed to arm-crank exercise. Group n = 12 Age: 27 ± 1 years Gender (M/F): Six males and six females BMI: 22.7 ± 0.7 kg/m² AC RER: 1.37 ± 0.03 LC RER: 1.26 ± 0.03
Study protocol
	AC or LC tested first: Not reported Time between tests: Not reported AC Start Watt: 30 LC Start Watt: 30 AC Watt increase/min: 20 W/min LC Watt increase: 15 W/min
Outcomes of interest	VO2_max and RER
Risk of bias	SumQAT: 6
Notes
Charbonnier, J. P. et al. (1975)
Title	Experimental study on the performance of competition swimmers.
Methods	Cross-sectional
Participant status	Six non-swimmers with a mean age of 31 ± 4 years, a mean height of 178 ± 3 cm and a mean bodyweight of 71 ± 5 kg. The swimmers were among the best in the country and the non-swimmers were members of the laboratory staff. Group n = 6 Age: 31 ± 4 years Gender (M/F): Three males and three females Height: 178 ± 3 cm Bodyweight: 71 ± 5 kg BMI: 22.41 kg/m² AC RER: 1.06 ± 0.01 LC RER: 1.04 ± 0.03
Study protocol
	AC or LC tested first: Not reported Time between tests: Not reported AC Start Watt: Not reported LC Start Watt: Not reported AC Watt increase/min: Not reported LC Watt increase: Not reported
Outcomes of interest	VO2_max and RER
Risk of bias	SumQAT: 5
Notes
Davies, C. T. M., & Sargeant, A. J. (1974)
Title	Indirect determination of maximal aerobic power output during work with one or two limbs.
Methods	Cross-sectional
Participant status	12 healthy male subjects. All except four subjects were accustomed to physical investigations. Group n = 12 Age: 30.5 ± 6.2years Gender (M/F): only males Height: 178.2 ± 5.1 cm Bodyweight: 75.1 ± 10.1 kg BMI: 23.65 kg/m²
Study protocol
	AC or LC tested first: Not reported Time between tests: Not reported AC Start Watt: Not reported LC Start Watt: Not reported AC Watt increase/min: Not reported LC Watt increase: Not reported
Outcomes of interest	VO2_max
Risk of bias	SumQAT: 1
Notes
Davis, J. A. et al (1976)
Title	Anaerobic threshold and maximal aerobic power for three modes of exercise.
Methods	Cross-sectional
Participant status	39 healthy university male students. None of them had been endurance training four months prior to the experiment. Nine of the 39 subjects participated only in the validation period. Group n = 30 Age: 22.5 ± 2.6 years Gender (M/F): only males Height: 179.8 ± 6.9 cm Bodyweight: 75.5 ± 9.0 kg BMI: 23.35 kg/m²
Study protocol
	AC or LC tested first: Not reported Time between tests: One day AC Start Watt: not reported LC Start Watt: not reported AC Watt increase/min: not reported LC Watt increase: not reported
Outcomes of interest	VO2_max
Risk of bias	SumQAT: 4
Notes
Dekerle, J. et al. (2002)
Title	Ventilatory thresholds in arm and leg exercices with spontaneously chosen crank and pedal rates.
Methods	Cross-sectional
Participant status	20 male students in physical education with a mean age of years, a mean height of cm and a mean bodyweight of kg. Group n = 12 Age: 22 ± 2.2 years Gender (M/F): only males Height: 180 ± 6 cm Bodyweight: 73.5 ± 5.3 kg BMI: 22.69 kg/m² AC RER: 1.2 ± 0.1 LC RER: 1.2 ± 0.1
Study protocol
	AC or LC tested first: not reported Time between tests: Within one week AC Start Watt: 30 LC Start Watt: 60 AC Watt increase/min: 15 LC Watt increase: 30
Outcomes of interest	VO2_max and RER
Risk of bias	SumQAT: 4
Notes
Franklin, B. A. et al. (1983)
Titel	Aerobic requirements of arm ergometry: implications for exercise testing and training
Methods	Cross-sectional
Participant status	10 healthy male subjects. Group n = 10 Age: 28 ± 2.4 years Gender (M/F): only males Height: 170.7 ± 7.5 cm Bodyweight: 69.3 ± 7.1 kg BMI: 23.78 kg/m² AC RER: 1.06 ± 0.09 LC RER: 1.12 ± 0.11
Study protocol
	AC or LC tested first: not reported Time between tests: One day AC Start Watt: not reported LC Start Watt: not reported AC Watt increase/min: not reported LC Watt increase: not reported
Outcomes of interest	VO2_max and RER
Risk of bias	SumQAT: 2
Notes	The study reports a correlation coefficient between AC and LC on r = 0.32.
Franssen, F. M. et al. (2002)
Title	Arm mechanical efficiency and arm exercise capacity are relatively preserved in chronic obstructive pulmonary diseas
Methods	Cross-sectional
Participant status	Controls, male/female (14/6) did not participate in any exercise-training program and were found through an advertisement in the local newspaper Group n = 20 Age: 61 ± 1 years Gender (M/F): 14 males and six females BMI: 25.9 ± 0.6 kg/m² AC RER: 1.22 ± 0.02 LC RER: 1.23 ± 0.02
Study protocol
	AC or LC tested first: not reported Time between tests: One week AC Start Watt: not reported LC Start Watt: not reported AC Watt increase/min: not reported LC Watt increase: not reported
Outcomes of interest	VO2_max and RER
Risk of bias	SumQAT: 4
Notes
Javierre, C. et al. (2007)
Title	Physiological responses to arm and leg exercise in women with chronic fatigue syndrome.
Methods	Cross-sectional
Participant status	15 healthy controls that were extremely sedentary. Their occupation did not require physical effort, they did not perform physical activity and or their hobbies were sedentary. Group n = 15 Age: 61 ± 1 years Gender (M/F): only females Bodyweight: 57.5 ± 5.1 kg Height: 159 ± 5 cm BMI: 22.74 kg/m² AC RER: 1.05 ± 0.11 LC RER: 1.08 ± 0.09
Study protocol
	AC or LC tested first: AC Time between tests: 10 minutes AC Start Watt: 10 LC Start Watt: 0 AC Watt increase/min: 10 W/min LC Watt increase: 12.5 W/min
Outcomes of interest	VO2_max and RER
Risk of bias	SumQAT: 6
Notes
Keteyian, S. et al. (1994)
Title	Cardiovascular responses of cardiac transplant patients to arm and leg exercise.
Methods	Cross-sectional
Participant status	10 healthy normal men. Five healthy subjects performed leg exercise three or more times per week and one healthy adult performed arm and leg exercise three times per week. Group n = 15 Age: 51 ± 5 years Gender (M/F): only males Bodyweight: 80.4 ± 15.6 kg
Study protocol
	AC or LC tested first: Random Time between tests: One hour AC Start Watt: 15 LC Start Watt: 30 AC Watt increase/min: 15 W/min LC Watt increase: 10 W/min
Outcomes of interest	VO2_max
Risk of bias	SumQAT: 3
Notes
Lewis, S. et al. (1980)
Title	Transfer effects of endurance training to exercise with untrained limbs
Methods	RCT
Participant status	Five healthy male college students. Group n = 5 Age: 22 ± 2 years Gender (M/F): only females Bodyweight: 79 ± 13 kg Height: 186 ± 10 cm BMI: 22.84 kg/m² AC RER: 1.27 ± 0.06 LC RER: 1.28 ± 0.07
Study protocol
	AC or LC tested first: Random Time between tests: Within one week AC Start Watt: 25 LC Start Watt: 50 AC Watt increase/min: 7 W/min LC Watt increase: 33 W/min
Outcomes of interest	VO2_max
Risk of bias	SumQAT: 6
Notes
Loughney, L. et al. (2014)
Title	Comparison of oxygen uptake during arm or leg cardiopulmonary exercise testing in vascular surgery patients and control subjects
Methods	Cross-sectional
Participant status	Twenty healthy control subjects . Group n = 20 Age: 31 (24–42) years Gender (M/F): 10 males and 10 females BMI: 26 (24–28) kg/m²
Study protocol
	AC or LC tested first: not reported Time between tests: not reported AC Start Watt: not reported LC Start Watt: not reported AC Watt increase/min: not reported LC Watt increase: not reported
Outcomes of interest	VO2_max and RER
Risk of bias	SumQAT: 5
Notes	The study reports a correlation coefficient between AC and LC on r = 0.77.
Louhevaara, V. et al. (1990)
Title	Differences in cardiorespiratory responses during and after arm crank and cycle exercise.
Methods	Cross-sectional
Participant status	21 untrained healthy men. Group n = 21 Age: 33.3 ± 5.9 years Gender (M/F): only males Bodyweight: 78.3 ± 12.7 kg Height: 178.4 ± 7.2 cm BMI: 24.6 kg/m² AC RER: 1.09 ± 0.08 LC RER: 1.17 ± 0.01
Study protocol
	AC or LC tested first: LC Time between tests: 2-7 days between AC Start Watt: 25 LC Start Watt: 50 AC Watt increase/min: 25 W/min LC Watt increase: 50 W/min
Outcomes of interest	VO2_max and RER
Risk of bias	SumQAT: 3
Notes
Lyons, S. et al. (2007)
Title	Excess post-exercise oxygen consumption in untrained men following exercise of equal energy expenditure: comparisons of upper and lower body exercise
Methods	Cross-sectional
Participant status	The subjects were recruited from the local university and city community, and consisted of individuals who were already participating in at least 30 min of moderate recreational physical activity on most days of the week. Group n = 10 Age: 25.7 ± 5.83 years Gender (M/F): only males Bodyweight: 104.9 ± 18.71 kg Height: 183.6 ± 6.73 cm BMI: 31.12 kg/m² AC RER: 1.09 ± 0.08 LC RER: 1.17 ± 0.01
Study protocol
	AC or LC tested first: Random Time between tests: not reported AC Start Watt: 12 LC Start Watt: 50 AC Watt increase/min: 6.25 W/min LC Watt increase: 17.5 W/min
Outcomes of interest	VO2_max and RER
Risk of bias	SumQAT: 6
Notes
McConnell, T. R. et al. (1984)
Title	The hemodynamic and physiologic differences between exercise modalities
Methods	Cross-sectional
Participant status	Healthy subjects. Group n = 10 Age: 29.4 years Gender (M/F): Five males and five females Bodyweight: 63.5 AC RER: 1.09 ± 0.08 LC RER: 1.17 ± 0.01
Study protocol
	AC or LC tested first: Random Time between tests: Within one week AC Start Watt: not reported LC Start Watt: not reported AC Watt increase/min: not reported LC Watt increase: not reported
Outcomes of interest	VO2_max and RER
Risk of bias	SumQAT: 3
Notes
Nag, P. K. (1984)
Title	Circulo-respiratory responses to different muscular exercises
Methods	Cross-sectional
Participant status	Five young men, free from any cardiovascular. They actively participated habitually in moderately heavi agricultural work, none were the limb and trunk muscles specially trained. Group n = 5 Age: 22.7 ± 3.4 years Gender (M/F): only males Bodyweight: 48.9 ± 0.9 kg Height: 160.2 ± 2.0 cm BMI: 19.05 kg/m² AC RER: 1.2 LC RER: 1.01
Study protocol
	AC or LC tested first: Random Time between tests: not reported AC Start Watt: 50-75 LC Start Watt: 50-75 AC Watt increase/min: 25-50 LC Watt increase: 25-50
Outcomes of interest	VO2_max and RER
Risk of bias	SumQAT: 3
Notes
Orr, J. L. et al. (2013)
Title	Cardiopulmonary exercise testing: arm crank vs cycle ergometry
Methods	Cross-sectional
Participant status	Fifteen healthy women were recruited from the University of Dundee. Group n = 15 Age: 23.5 ± 3.7 years Gender (M/F): Only females Bodyweight: 60.6 ± 7.8 kg Height: 167 ± 5 cm BMI: 21.73 kg/m²
Study protocol
	AC or LC tested first: Random Time between tests: 30 minutes AC Start Watt: 15 LC Start Watt: 25 AC Watt increase/min: 25-50 LC Watt increase: 25
Outcomes of interest	VO2_max
Risk of bias	SumQAT: 5
Notes
Pogliaghi, S. et al. (2006)
Title	Adaptations to endurance training in the healthy elderly: arm cranking versus leg cycling
Methods	RCT study
Participant status	18 men were recruited by local advertisements in the metropolitan area of Verona (Italy). Group “arm” n = 6, “leg” n = 6, “c” n = 6 Age: “arm” 68 ± 4, “leg” 66 ± 5, “c” 73 ± 4 years Gender (M/F): only males Bodyweight: “arm” 74 ± 6, “leg” 76 ± 11, “c” 80 ± 8 kg Height: “arm” 172 ± 4, “leg” 169 ± 6, “c” 173 ± 8 cm BMI: “arm” 25 ± 2 kg/m², “leg” 27 ± 3 kg/m², “c” 27 ± 2 kg/m² AC RER: 1.2 ± 0.1, “leg” 1.2 ± 0.1, “c” 1.1 ± 0.07 LC RER: 1.2 ± 0.07, “leg” 1.2 ± 0.06, “c” 1.2 ± 0.05
Study protocol
	AC or LC tested first: Random Time between tests: 60 minutes AC Start Watt: 40 LC Start Watt: 50 AC Watt increase/min: 5 LC Watt increase: 10
Outcomes of interest	VO2_max and RER
Risk of bias	SumQAT: 7
Notes
Protas, E. J. et al. (1996)
Title	Cardiovascular and metabolic responses to upper- and lower-extremety exercise in men with idiopathic Parkinson's disease.
Methods	Cross-sectional study
Participant status	7 control subjects from the local community with a mean age of 65 (53-71) were recruited. The controls were more sedentary than the PD group. Group n = 7 Age: 53-71 Gender (M/F): only males AC RER: 1.07 (1.0-1.18) LC RER: 1.12 (1.01-1.23)
Study protocol
	AC or LC tested first: Random Time between tests: 20 minutes AC Start Watt: 10 LC Start Watt: 20 AC Watt increase/min: 5 LC Watt increase: 10
Outcomes of interest	VO2_max and RER
Risk of bias	SumQAT: 3
Notes
Rathnow, K. M., & Mangum, M. (1990)
Title	Cardiopulmonary exercise testing: arm crank vs. cycle ergometry
Methods	Cross-sectional
Participant status	The single mode treatment group consisted of six males and three females. The mixed mode treatment group consisted of five males and three females. Due to the presentation of data in the study, and mixture of sexes in the groups this study will appear with no demographic data. Group “Mixed” n = 8, “Single” n = 9, “control” n = 7 Gender (M/F): “Mixed” five males and three females, “Single” six males and three females, “control” three males and four females. AC RER: 1.09 ± 0.08, “Single” 1.08 ± 0.08, “control” 1.07 ± 0.07 LC RER: 1.15 ± 0.08, “Single” 1.16 ± 0.08, “control” 1.07 ± 0.06
Study protocol
	AC or LC tested first: LC Time between tests: at least 20 minutes AC Start Watt: 15 LC Start Watt: 50-150 AC Watt increase/min: 25-50 LC Watt increase: 50
Outcomes of interest	VO2_max and RER
Risk of bias	SumQAT: 5
Notes
Reybrouck, T. et al. (1975)
Title	Limitations to maximum oxygen uptake in arm, leg and combined arm and leg ergometry.
Methods	Cross-sectional
Participant status	The untrained subject was 25 years old. Group n = 1 Age: 25 years Gender (M/F): only males AC RER: 0.95 ± 0.03 LC RER: 1.16 ± 0.05
Study protocol
	AC or LC tested first: not reported Time between tests: not reported AC Start Watt: not reported LC Start Watt: not reported AC Watt increase/min: not reported LC Watt increase: not reported
Outcomes of interest	VO2_max and RER
Risk of bias	SumQAT: 4
Notes
Ramonatxo, M. er al. (1996).
Title	Differences in mouth occlusion pressure and breathing pattern between arm and leg incremental exercise.
Methods	Cross-sectional study
Participant status	Eight normal male subjects. No subjects were involved in exercise training but all maintained their accustomed exercise training. Group n = 8 Gender (M/F): only males Age: 20-35 Heigh: 167-183 cm Weight: 60-80 kg
Study protocol
	AC or LC tested first: Random Time between tests: Within one week AC Start Watt: 25 LC Start Watt: 50 AC Watt increase/min: 6.25 LC Watt increase: 12.5
Outcomes of interest	VO2_max
Risk of bias	SumQAT: 3
Notes
Rösler, K. et al (1985)
Title	Transfer effects in endurance exercise.
Methods	Trial
Participant status	Ten healthy male subjects with a mean age of 30.5 (23-37) years, a mean height of 178 (172-182) cm and a mean bodyweight of 70.8 (64-83) kg. None of them had been involved in regular training during the preceding two years, although some of then did some recreational jogging or cycling. Group n = 10 Age: 30.5 (23-37) years Gender (M/F): only males Bodyweight: 70.8 (64-83) kg. Height: 178 (172-182) BMI: 22.35 kg/m²
Study protocol
	AC or LC tested first: not reported Time between tests: not reported AC Start Watt: 40 LC Start Watt: 100 AC Watt increase/min: 6.667 W/min LC Watt increase: 17.5 W/min
Outcomes of interest	VO2_max
Risk of bias	SumQAT: 4
Notes
Sargeant, A. J., & Davies, C. T. M. (1973).
Title	Perceived exertion during rhythmic exercise involving different muscle mass
Methods	Cross-sectional study
Participant status	Six healthy male subjects. All of the subjects had taken part of physiological investigations before and were habituated to the exercise modalities in the study. All of the physical characteristics are given individually. The age ranges from 24-39 years, the height ranges from 171.8-189.0 cm and the bodyweight from 63.0-98.0 kg. Group n = 6 Sex (M/F) = 6/0 Age: 30.6 ± 5.53 years Gender (M/F): only males Bodyweight: 79.1 ± 11.68 kg Height: 179.4 ± 5.98 cm BMI: 24.58 kg/m²
Study protocol
	AC or LC tested first: not reported Time between tests: not reported AC Start Watt: not reported LC Start Watt: not reported AC Watt increase/min: not reported LC Watt increase: not reported
Outcomes of interest	VO2_max
Risk of bias	SumQAT: 2
Notes
Sawka, M. N. Et al. (1983)
Title	Physiological factors affecting upper body aerobic exercise
Methods	Cross-sectional study
Participant status	Nine male subjects. Group n = 9 Sex (M/F): 9/0 Gender (M/F): only males Gender (M/F): 1/0 Bodyweight: 79.8 ± 7.8 kg
Study protocol
	AC or LC tested first: AC Time between tests: Two weeks AC Start Watt: not reported LC Start Watt: not reported AC Watt increase/min: not reported LC Watt increase: not reported
Outcomes of interest	VO2_max
Risk of bias	SumQAT: 2
Notes	The study reports a correlation coefficient between AC and LC on r = 0.94.
Sharp, M. A. et al. (1988)
Title	Maximal aerobic capacity for repetitive lifting: comparison with three standard exercise testing modes
Methods	Cross-sectional study
Participant status	18 male subjects. Group n = 18 Gender (M/F): only males Age: 23.9 ± 3.7 years Bodyweight: 75.9 ± 8.8 kg Height: 177.7 ± 8.9 kg BMI: 24.04 kg/m² AC RER: 1.19 ± 0.11 LC RER: 1.21 ± 0.09
Study protocol
	AC or LC tested first: not reported Time between tests: not reported AC Start Watt: not reported LC Start Watt: not reported AC Watt increase/min: not reported LC Watt increase: not reported
Outcomes of interest	VO2_max and RER
Risk of bias	SumQAT: 2
Notes
Shiomi, T. et al. (2000)
Title	Physiological responses and mechanical efficiency during different types of ergometric exercises.
Methods	Cross-sectional study
Participant status	Seven healthy male. No subjects were performing regular exercise and none had orthopaedic diseases. The subjects performed the tests at least two hours after the last meal and did not exercise before the tests. Group n = 7 Gender (M/F): only males Age: 32.1 (27-36) years Bodyweight: 64.1 (54-73) kg Height: 169.9 (163-180) cm BMI: 22.21 kg/m²
Study protocol
	AC or LC tested first: not reported Time between tests: not reported AC Start Watt: 20 LC Start Watt: 20 AC Watt increase/min: 20 W/min LC Watt increase: 20 W/min
Outcomes of interest	VO2_max
Risk of bias	SumQAT: 4
Notes	The study reports a correlation coefficient between AC and LC on r = 0.78.
Sporer, B. C. et al. (2007)
Title	Entrainment of breathing in cyclists and non-cyclists during arm and leg exercise
Methods	Cross-sectional study
Participant status	Eight control subjects. Group n = 8 Gender (M/F): only males Age: 26 ± 5 years years Bodyweight: 82.8 ± 8.1 kg Height: 184.5 ± 6.5 cm BMI: 24.32 kg/m²
Study protocol
	AC or LC tested first: Random Time between tests: 60 minutes AC Start Watt: 15 LC Start Watt: 30 AC Watt increase/min: 15 W/min LC Watt increase: 30 W/min
Outcomes of interest	VO2_max
Risk of bias	SumQAT: 5
Notes
Swensen, T. C., & Howley, E. T. (1993)
Title	Effect of one- and two-leg training on arm and two-leg maximum aerobic power
Methods	RCT
Participant status	21 untrained college-age men participated. They had a mean age of 22.8 (19-32) years and a mean bodyweight of 73 (45-91) kg. Group “control” n = 5, “two leg” n = 7, “one leg” n = 9 Age: not reported Gender (M/F): only males AC RER: “control” 1.16 ± 0.02, “two leg” 1.13 ± 0.07, “one leg” 1.16 ± 0.06 LC RER: “control” 1.16 ± 0.04, “two leg” 1.18 ± 0.07, “one leg” 1.22 ± 0.05
Study protocol
	AC or LC tested first: LC Time between tests: at least 20 minutes AC Start Watt: 70 LC Start Watt: 120 AC Watt increase/min: 10 W/min LC Watt increase: 15 W/min
Outcomes of interest	VO2_max and RER
Risk of bias	SumQAT: 5
Notes
Turner, D. L. et al. (1997)
Title	Effects of endurance training on oxidative capacity and structural composition of human arm and leg muscles.
Methods	Trial
Participant status	Six healthy male subjects. None of the subjects trained systematically although they were recreationally active. Group n = 6 Gender (M/F): only males Age: 23 ± 1 years Bodyweight: 75 ± 2 kg Height: 179 ± 1 cm BMI: 23.41 kg/m²
Study protocol
	AC or LC tested first: not reported Time between tests: not reported AC Start Watt: 54 LC Start Watt: 50 AC Watt increase/min: not reported LC Watt increase: not reported
Outcomes of interest	VO2_max
Risk of bias	SumQAT: 6
Notes
Warren, G. L. et al. (1990)
Title	Is gender difference in peak VO₂ greater for arm than leg exercise?
Methods	Cross sectional study
Participant status	The untrained subjects had not participated in any form of regular aerobic exercise or strength training three months prior to the study. Group n = 10 Gender (M/F): only females Age: 25.1 ± 2.8 years Bodyweight: 54.3 ± 7.1 kg Height: 161 ± 4 cm BMI: 20.95 kg/m²
Study protocol
	AC or LC tested first: Random Time between tests: two days AC Start Watt: 6-12 LC Start Watt: 30-47 AC Watt increase/min: not reported LC Watt increase: not reported
Outcomes of interest	VO2_max
Risk of bias	SumQAT: 5
Notes
Yasuda, N., et al. (2008)
Title	No gender-specific differences in mechanical efficiency during arm or leg exercise relative to ventilatory threshold
Methods	Cross sectional study
Participant status	The women had a mean age of 23.4 ± 3.6 years, mean BMI 22.8 ± 2.1 units, a mean height of 167.3 ± 6.2 cm and a mean bodyweight of 63.6 ± 5.5 kg. Group n = 9 Gender (M/F): only females Age: 23.4 ± 3.6 years Bodyweight: 63.6 ± 5.5 kg Height: 167.3 ± 6.2 cm BMI: 22.28 ± 2.1 kg/m² AC RER: 1.08 ± 0.05 LC RER: 1.12 ± 0.06
Study protocol
	AC or LC tested first: Random Time between tests: Within 14 days AC Start Watt: 20 LC Start Watt: 97 AC Watt increase/min: 5 W/min LC Watt increase: 18 W/min
Outcomes of interest	VO2_max
Risk of bias	SumQAT: 5
Notes
Yasuda, N., et al. (2006)
Title	Substrate oxidation during incremental arm and leg exercise in men and women matched for ventilator threshold
Methods	Cross sectional study
Participant status	The subject performed low intensity exercises, such as running og cycling, for less than 1 hour per week for a maximum of 4 times per week. Group n = 10 Gender (M/F): 0/10 Age: 23.4 ± 3.4 years Bodyweight: 62.5 ± 6.2 kg Height: 166 ± 7 cm BMI: 22.68 kg/m² AC RER: 1.10 ± 0.07 LC RER: 1.12 ± 0.06
Study protocol
	AC or LC tested first: Random Time between tests: Within 7 days AC Start Watt: 20 LC Start Watt: 97 AC Watt increase/min: 5 W/min LC Watt increase: 18 W/min
Outcomes of interest	VO2_max
Risk of bias	SumQAT: 5
Notes