title: Does a run/walk strategy decrease cardiac stress during a marathon in non-elite runners?
abstract: OBJECTIVE
  Although alternating run/walk-periods are often recommended to novice runners, it is unclear, if this particular pacing strategy reduces the cardiovascular stress during prolonged exercise. Therefore, the aim of the study was to compare the effects of two different running strategies on selected cardiac biomarkers as well as marathon performance.
  
  
  METHODS
  Randomized experimental trial in a repeated measure design.
  
  
  METHODS
  Male (n=22) and female subjects (n=20) completed a marathon either with a run/walk strategy or running only. Immediately after crossing the finishing line cardiac biomarkers were assessed in blood taken from the cubital vein. Before (-7 days) and after the marathon (+4 days) subjects also completed an incremental treadmill test.
  
  
  RESULTS
  Despite different pacing strategies, run/walk strategy and running only finished the marathon with similar times (04:14:25±00:19:51 vs 04:07:40±00:27:15 [hh:mm:ss]; p=0.377). In both groups, prolonged exercise led to increased B-type natriuretic peptide, creatine kinase MB isoenzyme and myoglobin levels (p<0.001), which returned to baseline 4 days after the marathon. Elevated cTnI concentrations were observable in only two subjects. B-type natriuretic peptide (r=-0.363; p=0.041) and myoglobin levels (r=-0.456; p=0.009) were inversely correlated with the velocity at the individual anaerobic threshold. Run/walk strategy compared to running only reported less muscle pain and fatigue (p=0.006) after the running event.
  
  
  CONCLUSIONS
  In conclusion, the increase in cardiac biomarkers is a reversible, physiological response to strenuous exercise, indicating temporary stress on the myocyte and skeletal muscle. Although a combined run/walk strategy does not reduce the load on the cardiovascular system, it allows non-elite runners to achieve similar finish times with less (muscle) discomfort.
authors.affiliation: Department Sport Science, Martin-Luther-Universität Halle-Wittenberg, Germany; Institute of Performance Diagnostics and Health Promotion, Martin-Luther-Universität Halle-Wittenberg, Germany. Electronic address: kuno.hottenrott@sport.uni-halle.de.
authors.forename: Kuno
authors.initials: K
authors.lastname: Hottenrott
authors.affiliation: Institute of Performance Diagnostics and Health Promotion, Martin-Luther-Universität Halle-Wittenberg, Germany. Electronic address: sebastian.ludyga@ilug.de.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Ludyga
authors.affiliation: Department Sport Science, Martin-Luther-Universität Halle-Wittenberg, Germany; Institute of Performance Diagnostics and Health Promotion, Martin-Luther-Universität Halle-Wittenberg, Germany. Electronic address: stephan.schulze@sport.uni-halle.de.
authors.forename: Stephan
authors.initials: S
authors.lastname: Schulze
authors.affiliation: Department Sport Science, Martin-Luther-Universität Halle-Wittenberg, Germany; Institute of Performance Diagnostics and Health Promotion, Martin-Luther-Universität Halle-Wittenberg, Germany. Electronic address: thomas.gronwald@sport.uni-halle.de.
authors.forename: Thomas
authors.initials: T
authors.lastname: Gronwald
authors.affiliation: Cardiological Clinic Kassel, Germany. Electronic address: info@kardio-praxis-ks.de.
authors.forename: Frank-Stephan
authors.initials: FS
authors.lastname: Jäger
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D052279:Creatine Kinase, MB Form / Q000097:blood*; D005260:Female; D064368:Healthy Volunteers; D006321:Heart / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D012420:Running / Q000502:physiology*; D013312:Stress, Physiological; D014336:Troponin / Q000097:blood*; D016138:Walking / Q000502:physiology*
chemical_list: D015415:Biomarkers; D014336:Troponin; D020097:Natriuretic Peptide, Brain; D052279:Creatine Kinase, MB Form
keywords: Brain natriuretic peptide; Cardiac troponin; Marathon; Pacing strategy; Recreational runners