Relative muscle activity in different trials. sEMG levels of soleus (A) and gastrocnemius medialis (B) at different force levels in eccentric (ECC), isometric (ISO) and concentric (CON) contractions.

<p>sEMG is expressed relative to maximal isometric contraction (MVC). Significant differences between conditions and force-levels: *  = p<.05, **  = p<.01, ***  = p<.001.</p

Within groups means pre and post intervention, between groups difference (mean ± standard error) from baseline to 12-months follow-up and percentage change relative to the baseline mean of the randomized population of cleaners (N = 116).

<p>Within groups means pre and post intervention, between groups difference (mean ± standard error) from baseline to 12-months follow-up and percentage change relative to the baseline mean of the randomized population of cleaners (N = 116).</p

Examples of ISO, CON and ECC trials from one subject at 10% MVC.

<p>TOP: Cursors 1 and 2 mark the beginning and end of analysis, respectively. In dynamic contractions Cursor 1 is 200 ms prior and Cursor 2 200 ms after the angle crosses the angle of the ISO trial, as indicated by the horizontal cursor. BOTTOM: 400 ms close-ups of the wire EMG signal of each trial.</p

Flow of the participants.

<p>Flow of the participants.</p

Between groups means pre and post intervention stratified on baseline level of aerobic workload (≥ or <30% HRR), between groups difference (mean ± standard error) from baseline to 12-months follow-up (N = 116).

<p>Between groups means pre and post intervention stratified on baseline level of aerobic workload (≥ or <30% HRR), between groups difference (mean ± standard error) from baseline to 12-months follow-up (N = 116).</p

Number of subjects and motor units (MU), motor unit discharge rate (MUDR) and relative force and sEMG levels of soleus (SOL) and gastrocnemius medialis (GM) in different conditions.

<p>Force and sEMG levels are calculated relative to isometric MVC. *: significantly larger than in lower force level. ^† : significantly smaller than in CON. ^‡ : significantly smaller than in ECC (P<0.05).</p

Motor unit discharge rate (1/s; X±SD) at different relative force levels (%MVC) in eccentric (ECC), isometric (ISO) and concentric (CON) contractions.

<p>Significant differences between conditions and force-levels: *  = p<.05, **  = p<.01, ***  = p<.001.</p

Box plot (mean, SD and range) of the cardiorespiratory fitness divided by intervention group at baseline and 12-months of follow up.

<p>Blue represents baseline and green represents 12-months follow-up.</p

Discharge rates of motor units that could clearly be recognized in at least two of the three contraction types at 10 (solid line), 20 (dashed line) and 40% of MVC (dotted line).

<p>Discharge rates of motor units that could clearly be recognized in at least two of the three contraction types at 10 (solid line), 20 (dashed line) and 40% of MVC (dotted line).</p

Box plot (mean, SD and range) of the resting heart rate divided by intervention group at baseline and 12-months of follow up.

<p>Blue represents baseline and green represents 12-months follow-up.</p