Study design (if review, criteria of inclusion for studies)
Randomised controlled trial
24r adults with CF
Interval exercise (IE) compared to constant-load exercise (CLE) training. Patients were randomised to 30-min IE (100 % peak work capacity (WRpeak) for 30-s alternated with 40 % WRpeak for 30-s; nâ¯=â¯12) or 30-min CLE (70 % WRpeak; nâ¯=â¯12) training, 3 times weekly, for 12 weeks.
Isometric quadriceps muscle strength was assessed using a strain gauge Myometer.
The magnitude of improvement in quadriceps muscle strength was greater (pâ¯=â¯0.037) in the IE (by 32â¯Â±â¯13 Nm) compared to the CLE (by 23â¯Â±â¯12 Nm) groups. Maximum inspiratory and expiratory mouth pressures were significantly improved only in the IE group (by 30â¯Â±â¯10 cmH(2)O; pâ¯=â¯0.009 and 13â¯Â±â¯4 cmH(2)O; pâ¯=â¯0.007, respectively). Arterial oxygen saturation during training was higher (pâ¯=â¯0.002) for IE (94â¯Â±â¯1%) compared to CLE (91â¯Â±â¯1%), whereas dyspnoea scores were lower (pâ¯=â¯0.001) for IE (3.8â¯Â±â¯0.7) compared to CLE (5.9â¯Â±â¯0.8)
IE is superior to CLE in improving peripheral and respiratory muscle strength and preferable to CLE because it is associated with lower exercise-induced arterial oxygen desaturation and breathlessness.