Search Results

You are looking at 1 - 2 of 2 items for

  • Author: Nils Haller x
Clear All Modify Search
Restricted access

Nils Haller, Suzan Tug, Sarah Breitbach, Arne Jörgensen and Perikles Simon

Purpose:

Increases in concentrations of circulating cell-free DNA (cfDNA) have recently been demonstrated to occur in a variety of exhausting and vigorous exercise settings. Here, the authors assessed the association of cfDNA with exercise duration and intensity in a controlled test–retest setting of a regenerative up-to-moderate-level aerobic run.

Methods:

In a pretest, the lactate threshold (LT) was determined in 13 participants (range 10.8–13.4 km/h) by using a step-wise incremental running test. The speed of the 2 endurance runs was set to 9.6 km/h for 40 min; for the participants with an LT below the median (12.8 km/h; G1), this was a moderate aerobic run, and for those with an LT above the median, this was a regenerative run (G2). Capillary cfDNA, lactate, and rating of perceived exertion (RPE) were assessed before, every 10 min during, and after the runs.

Results:

During the last 30 min of the 2 runs, lactate did not increase, whereas cfDNA increased steadily (3.46-fold for G1 and 2.05-fold for G2). Intraclass correlation for cfDNA was high (r = .81, P < .0001) for all runners but higher for male participants (r = .92, P < .0001). The correlations of cfDNA and lactate with RPEs were r = .58 (P < .0001) and r = .32 (P < .05), respectively.

Conclusions:

Both duration and level of intensity were significantly associated with accumulation of cfDNA. The correlation with RPE and the high test–retest reliability suggest that cfDNA might be applicable as a marker to monitor individual training load for aerobic and intermittent exercises. Future randomized, controlled, longitudinal training studies will have to reveal the full potential of cfDNA as an exercise-physiology marker.

Restricted access

Nils Haller, Tobias Ehlert, Sebastian Schmidt, David Ochmann, Björn Sterzing, Franz Grus and Perikles Simon

Purpose: Player monitoring in elite sport settings is becoming increasingly important. Questionnaire-based methods and biomarkers such as circulating, cell-free DNA (cfDNA) are suggested for load monitoring. cfDNA concentrations were shown to increase depending on total distance covered in football and were associated with overtraining in weight lifters. Thus, the objective of this study was to examine whether cfDNA is feasible as a monitoring tool in elite football players. Methods: Capillary blood samples from 22 male elite football players were collected over 4 mo of a regular season. Sampling was conducted the day before, 1 day after, or several days after regular-season games and/or training. In addition, each player filled in a visual analogue scale (VAS) questionnaire including the items “general perceived exertion,” “muscular fatigue,” and “mental fatigue.” Performance during training and games was tracked by the Catapult system and with the OPTA system, respectively. Results: cfDNA values were significantly elevated in players the day after regular-season games (1.4-fold; P = .0004) in line with the scores of the VAS. Both parameters showed significantly higher values during midweek-game weeks. cfDNA concentrations correlated with training data, and VAS was correlated with the tracking of the season games. However, cfDNA and VAS did not correlate with each other. Conclusions: cfDNA concentrations at rest and VAS scores are influenced by previous load in professional football players. Future studies will reveal whether cfDNA might serve as a practically applicable marker for player load in football players.