Monitoring Training and Recovery during a Period of Increased Intensity or Volume in Recreational Endurance Athletes

Abstract

The purpose of the study was to examine the effects of progressively increased training intensity or volume on the nocturnal heart rate (HR) and heart rate variability (HRV), countermovement jump, perceived recovery, and heart rate-running speed index (HR-RS index). Another aim was to analyze how observed patterns during the training period in these monitoring variables were associated with the changes in endurance performance. Thirty recreationally trained participants performed a 10-week control period of regular training and a 10-week training period of either increased training intensity (INT, n = 13) or volume (VOL, n = 17). Changes in endurance performance were assessed by an incremental treadmill test. Both groups improved their maximal speed on the treadmill (INT 3.4 ± 3.2%, p < 0.001; VOL 2.1 ± 1.8%, p = 0.006). In the monitoring variables, only between-group difference (p = 0.013) was found in nocturnal HR, which decreased in INT (p = 0.016). In addition, perceived recovery decreased in VOL (p = 0.021) and tended to decrease in INT (p = 0.056). When all participants were divided into low-responders and responders in maximal running performance, the increase in the HR-RS index at the end of the training period was greater in responders (p = 0.005). In conclusion, current training periods of increased intensity or volume improved endurance performance to a similar extent. Countermovement jump and HRV remained unaffected, despite a slight decrease in perceived recovery. Long-term monitoring of the HR-RS index may help to predict positive adaptations, while interpretation of other recovery-related markers may need a more individualized approach.

Effects of Increased Load of Low- Versus High-Intensity Endurance Training on Performance and Physiological Adaptations in Endurance Athletes

“…Although the individual response magnitudes indicated more positive performance adaptations in HIG, the present statistical findings are in contrast to those of Stöggl and Sperlich 11 and Vesterinen et al, 24 who demonstrated superior performance adaptations of a more polarized intensity distribution with greater HIT load compared to highvolume LIT regimes. However, Ingham et al 25 and Nuuttila et al 26 found similar performance adaptations of high-volume LIT and HIT regimes, which is in line with the present findings and implies that similar performance progression can be achieved both by increased load of LIT and HIT during the preparation period in endurance athletes. In accordance with the hypothesis, increased load of HIT led to 3-4% better VO2max adaptations in running and roller-ski skating compared to increased load of LIT.…”

Validity of the Wrist-Worn Polar Vantage V2 to Measure Heart Rate and Heart Rate Variability at Rest

“…Although movement artifacts are not a similar problem in the resting measurements as they might be during exercise, movements during sleep may be a slight issue in restless sleepers. The current PPG recording started 0.5 h after detected sleep onset and continued for 4 h in line with protocols used in previous studies [ 33 , 34 ]. Since the first hours of sleep typically have the highest proportion of slow-wave sleep, representing the most restful and stable period of the night [ 35 ], the 4-h analysis period may speculatively have some benefits compared to the whole night recordings in terms of data quality.…”

Physiological, Perceptual, and Performance Responses to the 2-Week Block of High- versus Low-Intensity Endurance Training

“…It seems that the parasympathetic hyperactivity may be related to the overreaching/fatigue state itself rather than to the increased training load, as fatigue was not increased at the group level in the current study. The HRV response to the increased training load, an increase or decrease, seems to be individual, despite the type of training ( 25 ). Interestingly, nocturnal HR decreased significantly during the recovery period in the INT group, with no changes at any week in VOL.…”

“…The LT1 was set at 0.3 mmol·L −1 above the lowest lactate value and LT2 at the intersection point between 1) a linear model between LT1 and the next lactate point and 2) a linear model for the lactate points measured after the point when La increased at least 0.8 mmol·L −1 for the first time. The same treadmill and lactate threshold estimation protocols have been used in previous studies ( 16 , 24 , 25 ).…”