Table 2

Effects of energy conservation technique condition versus control condition on breathlessness and physiological variables at the end of exercise (intention-to-treat analysis)

VariablesEnergy conservation techniqueControlCondition effect
BaselineEnd-exerciseBaselineEnd-exerciseBetween conditions differences (95% CI) or (25th; 75th)P value
Breathlessness (mBorg)0.0 (0.0; 0.5)3.0 (2.0; 4.0)***0.0 (0.0; 1.0)5.0 (4.0; 6.0)***−1.00 (−3.50; −1.00)<0.001
Leg discomfort (mBorg)0.0 (0.0; 0.0)2.0 (0.0; 2.0)***0.0 (0.0; 0.0)3.0 (2.0; 5.0)***−1.00 (−3.00; 0.00)0.006
SpO2 (%)92.8 (3.5)85.3 (6.3)***93.1 (3.2)84.8 (7)***0.53 (−1.54; 2.61)0.6
StO2 (%)66.0 (6.1)57.8 (9.6)*67.9 (6.3)57.2 (8.3)***2.18 (−0.63; 4.99)0.12
Heart rate (bpm)85.5 (12.3)108.0 (13.6)86.7 (17.3)103.9 (22.2)5.26 (−6.01; 16.53)0.34
Respiratory rate (cpm)20.0 (18.0; 22.0)27.0 (23.0; 30.0)***20.5 (18.0; 22.0)28.0 (26.0; 32.0)***−1.00 (−4.00; 1.00)0.14
Minute ventilation (L/min)11.2 (3.5)19.1 (6.7)***10.9 (3.8)27.6 (8.6)***−8.68 (−12.00; −5.37)<0.001
Inspiratory capacity (L)1.8 (0.6)1.7 (0.5)*1.9 (0.7)1.5 (0.5)*0.14 (−0.02; 0.31)0.08
Lactate (mmol/L)2.1 (1.8; 2.7)2.9 (2.0; 3.4)**1.5 (1.4; 2.0)4.5 (3.5; 6.1)***−2.30 (−3.90; −1.10)0.013
Number of breaks (defined as break ≥ 10 s) 0.04100.0 (0.0; 0.0)3.0 (1.0; 4.0)<0.001
Total duration of breaks (s)0.0 (0.0; 0.0)54.0 (10.0; 140.0)−54.00 (−136.00; 0.00)<0.001
Total task time (s)372.5 (73.0)341.6 (128.5)30.91 (−58.64; 120.50)0.48
  • Continuous data are presented as means (SD) (or means and 95% CI for the difference between the two conditions) or medians (Q1; Q3) depending on the normality of the distribution. Effect of intervention, intervention sequence and the first-order carryover risk were analysed using a Student’s t-test or a Mann–Whitney test, depending on the normality of the distribution. Changes within each of the conditions were compared using a paired t-test or a Wilcoxon test, depending on normality.

  • mBorg, modified Borg scale from 0 to 10 (0: no fatigue or dyspnoea, 10: maximal effort); SpO2, pulsed O2 saturation. For HR, the median number of breaks taken during test and the total task time, there were a significant interactions with the order of the conditions tested (respectively p=0.0480 for HR, p=0.0410 for the median number of breaks and p=0.0158 for total task time); therefore, only the first sequence was analysed in each case.

  • *p<0.05 for before–after analysis of a condition; **p<0.01 for before–after analysis of a condition; ***p<0.001 for before–after analysis of a condition.