1. THE USE OF FATIGUE AND POWER AS EARLY INDICATORS OF OVERTRAINING IN FEMALE RUNNERS
Justin Nicoll1, Disa L. Hatfield1, Ryan Keith1, Kathleen Melanson2, Christopher Nasin3, Deborah Riebe1
Department of Kinesiology1, University of Rhode Island, Kingston, RI 02881
Department of Nutrition2, University of Rhode Island, Kingston, RI 02881
Health Services3, University of Rhode Island, Kingston, RI 02881
Abstract
Methods
Results
Overtraining (OT) is common in endurance sports. Current literature focuses on the mechanisms responsible for overtraining such as energy imbalance, hypothalamic imbalances, and autonomic neuromuscular function. However, there is little information concerning early symptoms that can be easily identified and monitored so training adjustments can be made and performance decrements avoided. PURPOSE: The purpose of this study was to describe the relationship between commonly cited overtraining symptoms of fatigue and performance (vertical jump power, race times) changes over a track season in female collegiate endurance athletes. METHODS: Sixteen female track and field mid and long distance runners (age: ± 1.47 yrs; height: ± 6.08 cm; body mass: ± 5.44 kg; VO2MAX: ± 5.92 ml/kg/min) participated in a 14-week descriptive study. Vertical jump power (W) was measured PRE, MID, and POST season. A fatigue scale was administered weekly. Percent change in race time (season best v.s. championship performance) was calculated. Pearson correlations were used to determine relationships between fatigue and performance variables. Repeated measures ANOVA with Bonferroni adjustment was used to determine differences in power output at different time points. Statistical significance was set at p ≤ RESULTS: Vertical jump power significantly increased PRE to MID season (2046 ± 213 W vs 2227 ± 269 W) and significantly deceased MID to POST (2227 ± 269 W vs 2102 ± 220 W). There was a significant correlation between fatigue (week 12) and changes in performance time (r =-.592). CONCLUSION: Administering simple fatigue scales several weeks prior to major competition may be a useful tool that predicts changes in forthcoming running performances. Preventing power decrements during competition season is an important factor to consider, as power is important during the starting “kick” of races to gain position, and sprinting to the finish line. Practical applications of this research indicate monitoring fatigue and power over the course of an athlete’s season may allow coaches and medical personnel to intervene when early symptoms of OT emerge. This will allow for adjustment of training programs before decreases in performance and overreaching or overtrained status occur.
Data was collected during the 2013 indoor & outdoor track and field season
Vertical jump power (VJP) was assessed at PRE, MID and POST
A fatigue scale was administered weekly
Body composition was assessed at PRE and POST
Figure 3
Power output at PRE, MID, and POST.
† indicates significantly different from PRE and POST. p≤0.05
*Indicates significantly different from PRE. p≤0.05
Middle Distance Runners n=7, Long Distance Runners n=6
Figure 4
Lean body mass change during the track and field season.
* indicates significantly different from PRE in corresponding group. p≤0.05
Middle Distance Runners n=7, Long Distance Runners n=6
Figure 1.
Timeline of data collection during the 2013 Indoor and Outdoor track and field season
Figure 2.
Weekly fatigue scale that was administered to athletes
Introduction
Overtraining is common in endurance sports. The mechanisms responsible for OT are difficult to identify, however energy imbalance, hypothalamic imbalances, and autonomic neuromuscular fatigue are important factors.
To be successful in sport, athletes must balance energy intake and energy expenditure (2), however not all athletes achieve energy balance (3) and may be subject to overtraining (1).
Research suggests psychological parameters may indicate overtraining before performance decrements become evident (5)
Little is known concerning early symptoms that can be easily identified and monitored, such that training adjustments can be made and performance decrements avoided.
Statistical Analysis
Percent change in race time (season best race time vs. championship meet race time) was used to determine improvements or decrements in running performance at end of season
Pearson correlations were performed between fatigue and performance variables (% change race time)
Repeated measures ANOVA was used to determine changes in vertical jump power, fatigue, and body composition the during season.
All data are presented in as Mean ± Std Error of Mean (M±SEM)
Significance was set at p≤ 0.05.
Figure 5
Fatigue at week 12 and running performance at the end of the season. r = , p= n=14
Figure 6
*; indicates significantly different from PRE in 800m group only. p≤0.05
Middle Distance Runners n=7, Long Distance Runners n=6.
Purpose
The purpose of this study was to describe the relationship between overtraining symptoms of fatigue, and performance (e.g. vertical jump power, race times) changes over a track season in female collegiate endurance athletes
Results
Power significantly increased in the middle (800m) distance runners from PRE to MID (2184 ± 70W vs 2408 ± 81W; p≤ 0.05) and significantly decreased from MID to POST (2408 ± 81W vs 2194 ± 76W; p≤ 0.05) See Figure 3.
Power significantly increased in the long (1500m) distance runners from PRE to MID ( W vs 2015 ± 57W; p≤ 0.05). See Figure 3.
Lean body mass (LBM) significantly decreased in the middle (800m) runners from PRE to POST (43.23 ± 15kg vs ± 15kg; p=0.017). See Figure 4.
There was a significant relationship between fatigue at week 12 and performance at the end of the season (r=-.592; p=0.031). See Figure 5.
Fatigue was significantly higher at week 12 and POST compared to PRE; p≤ Fatigue at week 12 and POST were not significantly different from each other (p≥ 0.05). See Figure 6.
Subjects
Discussion
Sixteen female track and field runners
Observed during the Indoor & Outdoor Track and Field season
Impaired power output (6) was also observed at the end of the season despite a taper (4). Increases in perceptions of fatigue were associated with performance staleness and power decrements.
Decreased power output has been reported in other sports. An effective taper can increase power, decrease fatigue, and decrease running time (4).
Decreases in power in the middle distance runners may have been due to losses in LBM.
Power is important at the start of races and for the “kick” to the finish line. Monitoring and avoiding decrements in power may be important for coaches to assess during the competiton season.
Monitoring power and administering simple fatigue scales several weeks prior to major competition may be a useful tool that assesses changes in forthcoming running performances.
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