title: Exercise-Induced Fatigue and Recovery in the Ageing Athlete
Creators: name: Fell, James
Publisher: name: Griffith University
Year: 2006
Subjects: subject: Exercise-induced fatigue
subject: recovery time from exercise
subject: ageing athlete
subject: well trained older adults

description: There is a common belief among older athletes that intense training becomes more difficult with ageing. One of the reasons attributed to this performance limitation is an impairment of recovery processes that can prolong the time taken for the body to adequately adapt between training sessions or after competition. However, there has been limited research to address this assumption through the investigation of recovery of performance after training or competition in well-trained older athletes. This thesis reviews the literature pertaining to ageing and exercise with particular reference to athletic performance, muscle damage and muscle repair/regeneration, with the intention of exploring the effects of ageing on training, overload and recovery from exercise in the well-trained ageing athlete. Two arguments are presented for an impaired recovery from training and competition in the older athlete. The first is that muscle damage after exercise is greater in the older athlete, and the second is that tissue repair is slower, both factors potentially prolonging recovery duration. The importance of adequate nutrition for recovery in athletes is recognised and discussed in regard to optimising recovery and to identify any specific dietary requirements or limitations that might be unique to the ageing athlete. Therefore, the aims of this thesis were to: 1. describe the common beliefs and practices amongst athletes regarding ageing and recovery from intense training and competition demands, 2. assess and compare the nutrient intake of young and ageing athletes via the completion of diet records, 3. quantify any differences between well-trained young and ageing athletes, that were matched for fitness and training variables, in their performance impairment, perceived physical impairment or rate of recovery after intense exercise. In addressing these aims four studies are presented. The first utilised a brief questionnaire administered as a method of subject recruitment for future studies. Thirty six athletes under 30 years of age (24 3 years) and sixty four athletes aged 30 years and above (41 8 years) provided responses to a series of questions pertaining to training history, current training activities, post exercise symptoms of fatigue, perception of recovery duration, and the use of recovery strategies. Results indicated that there were significant differences (p less than 0.05) between the young and older groups for training frequency (9 3 vs. 7 3 sessions per week), training volume (17 8 vs. 11 5 hours per week) and recovery duration (10 9 vs. 16 14 hours). There was also a significant positive correlation between recovery duration and training history (R=0.28, p less than 0.01). The majority of athletes surveyed indicated that they used specific strategies to promote recovery (76%). The second study compared the nutrient intake of young and veteran athletes (veteran: up to 35 years). The purpose of the dietary analysis was to establish if any apparent differences in recovery attributed to ageing could be a result of differing nutritional practices. Three-day diet record data from 13 young (24.0 ± 4.8 years) and 16 veteran (43.8 ± 5.0 years) athletes were collected and compared for differences in nutrient intake that might contribute to impaired recovery from exercise. Diet records were analysed by a qualified dietitian using the dietary analysis software Food Works (Xyris Software, Highgate Hill, Australia). Physical activity levels were assessed using the Baecke physical activity questionnaire. Energy expenditure was also estimated using the equations of Schofield and Harris-Benedict. The results indicated that there were no significant differences between young and veteran athletes for overall energy intake. However, the veteran athletes had a significantly higher percentage of daily energy intake from fat than the young athletes (35 5 vs. 29 6 g.day-1; p less than 0.05). The mean dietary intake of CHO for both age groups was substantially lower than the recommended guidelines for endurance athletes. The third and fourth studies compared measures/markers of recovery in nine young (23.7 ± 4.8 years) and nine veteran (44.3 ± 5.4 years) cyclists and triathletes that were matched for training and performance. Recovery was measured over three days (T1 to T3) of intense exercise that replicated heavy training and/or competition demands. Functional performance measures included a progressive maximal test, thirty-minute time trial performance (TT30), leg power (countermovement jump), leg strength (maximal voluntary isometric contraction), sprint cycling performance (10 second sprint) and analysis of blood markers associated with exercise induced muscle damage (creatine kinase, lactate dehydrogenase). Perceptual and report of recovery (psychological recovery) was assessed using verbally anchored Visual Analogue Scales used to measure motivation, muscle soreness (SOR), ratings of fatigue (FAT) and the total quality recovery scale (TQR). For the measures of functional performance there were no significant differences between the two age groups. Both groups maintained their time trial performance over the three days of intense endurance exercise. The average height jumped in the countermovement jump decreased slightly (2.6%, p less than 0.05) over the three days. There was also a significant decrease in average heart rate during the TT30 over the three days (~3 b.min-1) for both groups. In response to the testing protocols serum CK activity was significantly elevated for both age groups on days two and three (combined age data: T1- 122 ± 43, T2- 178 ± 90, T3- 166 ± 87, p less than 0.05). For the perception and report of soreness, fatigue and recovery, non-parametric statistics indicated that the veteran group reported a significant (P less than 0.05) change in SOR (6.2 ± 2.6 to 28.2 ± 14.1), FAT (1.7 ± 1.2 to 2.2 ± 0.09), and TQR (15.8 ± 2.5 to 13.8 ± 2.1) over the T1 to T3, while these changes in the young group were non-significant (SOR: 15.5 ± 15.5 to 24.2 ± 17.1, FAT: 1.7 ± 1.1 to 2.2 ± 0.9 and TQR: 16.3 ± 2.6 to 15.1 ± 2.9). The change in muscle soreness was significantly (p less than 0.05) greater in the veteran group than in the young group (Veteran, 22 ± 14; Young, 9 ± 12). This investigation has provided the first comprehensive description of recovery from exercise in well-trained veteran endurance athletes. The common perception of a delayed recovery with ageing was supported by the longer reported duration required to recover between intense training and competition in athletes 30 years and older. This slower recovery does not appear to be due to major dietary differences between young and veteran athletes. In contrast to the perception of slower recovery repeated days of intense endurance cycling exercise was similarly tolerated by young and veteran athletes with respect to performance. However, there is a greater change in the perception of, muscle soreness and significant changes in fatigue and recovery in veteran athletes. This finding has implications for the effective monitoring of training load in the older athlete.