Torres‐Castro 2016.

Study characteristics
Methods	Study design: prospective randomised cross‐over study comparing air (breath) stacking and glossopharyngeal breathing Study grouping: cross‐over 'Rescue' vs maintenance therapy: maintenance Ethics: informed consent was obtained from participants. Ethical approval was obtained from the Ethics Committee for Research Involving Human Beings, Faculty of Medicine, University of Chile. Additional information: the author provided selected separate period data on email request.
Participants	Baseline characteristics Overall sample data Sample size, n: 14 Age in years, median: 12.5 (range 9–18) Age at diagnosis in years, mean: 9.9 (SD 3.4) Gender (male/female), n: 8/6 Duration of NIV in months, mean: 25.6 (SD 8.7) FVC in mL, mean: 1529 (SD 517) FVC % predicted, mean: 62.2 (SD 31.9) FEV1 in mL, mean: 1243 (SD 502) FEV1 percentage of reference value, mean: 64.1 (SD 31.4) FEV1/FVC, mean: 82.7 (SD 15.5) MIP in cmH2O, mean: 57.5 (SD 10.8) MIP % predicted, mean: 57.9 (SD 13.9) MEP in cmH2O, mean: 40.7 (SD 22.2) MEP % predicted, mean: 31.5 (SD 21.3) PCF in L/min, median: 175 (IQR 130–200) Use of wheelchair, n (%): 14 (100) Diagnoses, n: DMD 7, SMA type II 3, nemaline myopathy 2, spinal cord injury 1, centronuclear myopathy 1 Receiving nocturnal NIV in bilevel mode, n (%): 14 (100) First‐period baseline data, as provided by author on request Breathstacking Sample size, n: 7 Height in cm, mean: 152.29 (SD 9.59) Age in years, mean: 12.29 (SD 1.6) Gender (male/female), n: 5/2 VC in mL, mean: 1392.86 (SD 458.83) PCF in L/min, mean: 162.86 (SD 77.40) Glossopharyngeal breathing Sample size, n: 7 Height in cm, mean: 147.57 (SD 18.32) Age in years, mean: 11.71 (SD 3.55) Gender (male/female), n: 4/3 VC in mL, mean: 1284.29 (SD 453.28) PCF in L/min, mean: 167.14 (SD 42.71) Inclusion criteria Diagnosis of NMD Aged 5–18 years Without respiratory exacerbation in past 30 days No prior use or knowledge of breathstacking or glossopharyngeal breathing techniques Ability to understand instructions Signed consent to participate Exclusion criteria Tracheostomy incomplete glottis closure (measured during insufflation manoeuvre)
Interventions	Intervention characteristics Air/ breathstacking Participant positioning: seated in wheelchair Technique description: participants were first trained in the execution of the technique for 10 min. A manual resuscitation bag (maximum capacity 1600 mL) was used to provide insufflations (LIFESAVER model 5345, Hudson, Temecula, California, USA), connected to a corrugated tube with an internal diameter of 22 mm, a 1‐way valve, and a pipette. A chest physiotherapist insufflated the participant during the inspiratory phase, requesting that they inspire as much air as possible. Washout after intervention: 40 min between interventions, which were all performed on the same day. Repetitions: 3 measurements of the technique were performed, and the highest reading recorded. Rest periods: participants rested for 5 min between each assessment. Glossopharyngeal breathing Participant positioning: seated in wheelchair Technique description: participants were first trained in the execution of the technique for 10 min. The participant was instructed to perform successive manoeuvres of "swallowing air" until the maximum volume achieve was maintained. Washout after intervention: 40 min between interventions, which were all performed on the same day. Repetitions: 3 measurements of the technique were performed, and the highest reading recorded. Rest periods: participants rested for 5 min between each assessment.
Outcomes	Primary and secondary outcomes were not explicitly identified. Baseline VC and postintervention MIC Outcome type: continuous Unit of measure: L Measurement: baseline VC and postintervention MIC were evaluated using a portable ventilometer device (FERRARIS Wright MK 8, Louisville, Colorado, USA). VC and MIC were measured by taking a maximal inspiration followed by a maximal expiration. Direction: higher was better Reporting: fully reported PCF Outcome type: continuous Unit of measure: L/min Measurement: PCF was assessed at baseline, and after interventions, with the participant in the seated position, using a peak flow meter (MiniWright, Clement Clarke International, Essex, England) and mask interface. Participants were instructed to cough as hard as possible into the flowmeter connected to his/her mouth. For an evaluation to be considered repeatable, ≥ 3 efforts were required, with a difference ≤ 10% and the highest value was recorded as the PCF. Direction: higher was better Reporting: fully reported Adverse events: not reported
Identification	Sponsorship source: no sponsorship source declared. Conflict of interest: no conflict‐of‐interest statement presented. Country: Santiago, Chile Setting: domiciliary NIV programme recipients, in the participants' own homes Comments: authors declared no competing interests exist. Author names: Rodrigo Torres‐Castro, Jordi Vilaró, Roberto Vera‐Uribe, Luis Vasconcello, Homero Puppo Institution: Rodrigo Torres‐Castro and Homero Puppo: Department of Kinesiology, University of Chile, Chile Jordi Vilaró: Faculty of Health Sciences Blanquerna, Research Group of Physiotherapy (GReFis) Roberto Vera‐Uribe and Luis Vasconcello: National Program of Non‐Invasive Ventilation, Ministry of Health, Chile Email: klgorodrigotorres@gmail.com Address: not provided
Notes	Additional separate‐period baseline and outcome data were provided by author on request.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "To minimize the risk of bias, the order of execution of each cough assistance technique was performed randomly for each participant." Quote: "Randomization was performed by a free software (for www.randomization.com) specifically designed for generating random number lists."
Allocation concealment (selection bias)	Unclear risk	Quote: "To minimize the risk of bias, the order of execution of each cough assistance technique was performed randomly for each participant. Comment: the article did not describe whether or how allocation concealment was achieved.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Quote: "A chest physiotherapist insufflated the patient during the inspiratory phase." Quote: "The protocol was implemented in the patients' homes by a trained chest physiotherapist." Comment: the chest physiotherapist was physically performing the insufflation interventions; therefore, it would be impossible to blind them. Similarly, the participants could not feasibly be blinded to allocation considering the nature of the interventions.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Quote: "A chest physiotherapist insufflated the patient during the inspiratory phase." Quote: "The protocol was implemented in the patients' homes by a trained chest physiotherapist." Quote: "Baseline PCF assessment was performed with the patient seated and with a respiratory physiotherapist monitoring the seal between the entire surface of the mask and the flowmeter to avoid any leakage." Comment: the baseline, intervention, and outcome assessments seem to have been performed by the same physiotherapist, who could not have been blinded to intervention allocation.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Comment: 3 participants were excluded after screening, but clear reasons for exclusion were not provided.
Selective reporting (reporting bias)	Low risk	Comment: all outcome measures listed in the protocol were reported.
Other bias	Unclear risk	Comment: the following factors placed this study at unclear risk of other bias. Short‐term cross‐over study, which might not be the optimal study design for a chronic condition such as NMD. Primary and secondary outcomes were not explicitly identified.