Run/walk: similar marathon time, less soreness

In one trial, 42 recreational marathoners ran either with planned walk breaks or the whole way. Run/walk finished in 4:14 on average and running-only in 4:08, a gap too small to be statistically clear in a group this size. The run/walk group reported less muscle pain and fatigue after the race. Heart strain markers rose in both groups, with no sign that run/walk lowered them, and were back to baseline 4 days later.

What it means in practice

Present run/walk as a valid way to finish a marathon that may leave you less sore, with a similar finish time in one small trial. Do not claim it is faster, and do not cite a specific walk-break pattern from this study. Do not claim walk breaks save energy.

The evidence

• Hottenrott, K., Ludyga, S., Schulze, S. et al. (2016). Does a run/walk strategy decrease cardiac stress during a marathon in non-elite runners?. Journal of Science and Medicine in Sport.

  The run/walk and run-only groups finished in similar times (4:14:25 vs 4:07:40, p=0.377). Both groups showed rises in BNP, CK-MB and myoglobin after the race, which returned to baseline by 4 days after the race, so run/walk did not lower cardiac load. The run/walk group reported less muscle pain and fatigue after the race (p=0.006).

  n=42

Why we call confidence low

One randomized trial of 42 non-elite marathoners supports it, and only its abstract could be read. The run/walk group's mean was about 7 minutes slower but not significantly so, which does not prove the times were equal.

Where it applies

Non-elite adult marathon runners finishing in about 4 hours.

Does not apply to: elite or sub-3-hour marathon racing; specific walk-break schemes (the trial's protocol was not verified); walking only when exhausted compared with planned breaks.