Table 2.

Summary of randomised controlled trials of cycle ergometry interventions on muscle mass, strength or function

Author, year, country	Population	Timing	Intervention	Comparator	Muscle mass, strength or functional outcome	Results
Berney, 2021, Australia [57]	162 ICU patients with sepsis or systemic inflammatory response syndrome ≥48 h MV and ICU LOS ≥4 d	<72 h	60 min FES cycling >/=5 days/week until ICU discharge; single leg allocation FES cycling and other leg without FES	Usual care (respiratory and functional mobility)	Primary: quadriceps strength Secondary: MRC-SS handgrip strength PFIT-s FSS-ICU SPPB 6MWT Katz ADL RF-CSA	Primary: no significant difference between groups for quadriceps strength at hospital discharge Secondary: no significant difference between groups for any secondary measures
Burtin, 2009, Belgium [58••]	90 S/MICU patients with predicted ICU LOS >7 d	Late (>5 d after ICU admission)	Cycle ergometry 5 days/week 20 min per session individually adjusted intensity Passive 20 cycles/min or active 2× 10 min bouts increasing intensity until hospital discharge	Usual care (respiratory physiotherapy + standardised mobility of UL and LL 5 days per week) ranging from passive to active depending on the capability	Primary: 6MWD Secondary: quadriceps strength Handgrip strength Berg Balance Scale FAC SF-36 (PF domain)	Primary outcome: higher 6MWD distance in intervention at hospital discharge (196 vs 143 m, p < 0.05) Secondary: quadriceps strength gain higher between ICU discharge and hospital discharge in intervention (p < 0.01); no significant difference between groups for handgrip strength; Berg Balance Scale and FAC at ICU and hospital discharge; higher SF-36 (PF domain) scores in the intervention group at hospital discharge (21 vs 15 points, p < 0.01)
Eggmann, 2018, Switzerland [59]	Mixed MV ICU patients with ICU LOS ≥72 h	<48 h	5× week (with weekends as clinically indicated) up to a maximum of 3 sessions per day, endurance cycling (20 min/d at pedalling rate of 20 cycles/min) up to a max of 60 min at full resistance; resistance training for UL and LL (active assisted, weighted), 8–12 reps with 2–5 sets at 5–80% of estimated 1RM max, functional mobility tasks	Usual care (early mobility, respiratory therapy and passive/active exercises)	Primary: 6MWD and FIM Secondary: quadriceps strength Handgrip strength MRC-SS FIM TUG test SF-36	Primary: no significant difference between groups for 6MWD and FIM at hospital discharge Secondary: no significant difference in secondary outcomes
Fossat, 2018, France [60]	314 ICU patients admitted to ICU <72 h before randomisation	<48 h	1× 15 min session of cycling, 1× 50 min session/day of EMS of bilateral quads, 5× week until ICU discharge	Usual care	Primary: MRC-SS Secondary: ICU Mobility Scale Katz ADL Barthel Index SF-36 RF-CSA	No significant difference between groups in MRC-SS at ICU discharge Secondary: no significant difference between groups for any secondary measures
Gama Lordello, 2020, Brazil [61]	234 ICU cardiac surgery patients	Within 6–8 h following extubation	2× day until ICU discharge Cycle ergometry active 10 min (5 min LL, 5 min UL)	2× day 10 min of active exercises for LL and UL repeated 10×	Primary: in-hospital steps per day Secondary: mobility level in different subgroups, i.e. gender, type of surgery, pre-ICU PA	No significant difference between groups for steps per day over three days following allocated intervention Secondary: no difference in steps per day between groups
Kho, 2019, Canada [62]	66 ICU <4 d of MV and <7 d ICU LOS	<72 h	5 sessions per week of 30 min passive, to active cycling until ICU discharge + usual care	Usual care	PFIT-s	No difference between groups for PFIT-s scores at hospital discharge
Machado, 2017, Brazil [63]	38 MV ICU patients with acute respiratory failure	Median 2 d	Cycle ergometry passive to active 20 min 20 cycles/min 5× week up to ICU discharge	Conventional physiotherapy (2× 30 min daily respiratory and functional mobility)	MRC-SS	Significant improvement in MRC-SS in intervention compared to control (8.45 vs 4.18 points, p = 0.005)
Nickels, 2020, Australia [64]	72 mixed ICU patients expected to MV >48 h	<96 h	30 min daily in bed cycling 1× day (up to 6 days per week)	Usual care (respiratory and functional mobility)	Primary: RF-CSA at Day 10 Secondary: RF and VI thickness MRC-SS Handgrip strength FSS-ICU 6MWT ICU Mobility Scale	Primary: no significant between group differences in muscle atrophy of RF-CSA at day 10 Secondary: no significant between group differences for secondary measures

ADL, activities of daily living; CSA, cross-sectional area; FAC, functional ambulation category; FES, functional electrical stimulation; FIM, functional independence measure; FSS-ICU, functional status score in the ICU; ICU, intensive care unit; LL, lower limb; LOS, length of stay; min, minutes; MICU, medical ICU; MRC-SS, Medical Research Council sum score; MV, mechanical ventilation; PA, physical activity; PFIT-s, Physical Function in ICU test scored; RF, rectus femoris; SICU, Surgical ICU; SF-36, Short Form 36 Questionnaire; SPPB, Short Physical Performance Battery; TUG test, timed up and go test; UL, upper limb; VI, vastus intermedius; 1RM max, one repetition maximum; 6MWT, six-minute walk test; 6MWD, six-minute walk distance; %, percentage