Giavedoni 2012.

Methods	Randomised controlled trial in which 1 leg received electrical stimulation and 1 leg received no stimulation. The choice of leg to receive stimulation was randomised.
Participants	11 participants were enrolled and all completed the study (5 men, mean FEV1 % predicted = 41 (SEM 6) %, mean age = 72 (SEM 3) yr). They were recruited within 48 hours of admission to hospital with an acute exacerbation of COPD.
Interventions	Intervention: electrical stimulation of the quadriceps of 1 leg using an asymmetric, biphase pulse wave at a frequency of 50 Hz, pulse width of 400 ms for 30 minutes per day, once per day for 14 days. Duty cycle was 8 s on, 20 s off. Intensity was set at the maximum that could be tolerated for each participant. 4 sessions were supervised (3 in hospital and 1 at home) with the rest performed unsupervised either in hospital or at home (after discharge). Adherence was optimised with 2 telephone calls following discharge and extra supervised sessions were offered if needed. Control: no stimulation
Outcomes	BMI (descriptive data only) Airflow obstruction via spirometry (descriptive data only) Quadriceps strength was measured as force generated during a maximum isometric voluntary contraction using a strain gauge
Notes	Study supported by the BLF. Investigator supported by ERS long‐term research fellowship
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "…the dominant leg was randomly allocated to treatment with NMES or no stimulation (control)." Details pertaining to the development of the randomisation sequence were not reported.
Allocation concealment (selection bias)	Unclear risk	No details given
Blinding of participants and personnel (performance bias) All outcomes	High risk	Neither participants nor investigators administering the intervention were blinded.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No mention of blinding for outcome assessors. This may have affected their outcome related to muscle strength.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Insufficient details on attrition to comment on whether this was a source of bias.
Selective reporting (reporting bias)	Unclear risk	No protocol available
Other bias	Low risk	Study appeared free from other sources of bias.