This study investigated chronic changes in cell free DNA (cf-DNA) and other biochemical markers throughout a college soccer season. Twenty three NCAA Division I male collegiate soccer players volunteered to participate in this study. Athletes were divided into two groups based upon their weekly average game time rating of session rating of perceived exertion (sRPE). Group 1 (G1, n = 13, age 21.7 ± 1.5 years, height 178.8 ± 6.9 cm, body mass 77.9 ± 6.5 kg), consisted mostly of starters, averaged greater than a weekly 1500 game time sRPE over a fifteen week Fall season. Group 2 (G2, n =10, age 20.6 ± 1.0 years, height 181.8 ± 7.4 cm, body mass 82.5 ± 10.5 kg) averaged less than 1500 game time sRPE. Venous blood samples were taken three times; preseason, approximately midseason and postseason. In G1, cf-DNA (P = 0.001), CRP (P = 0.000), CK (P = 0.003), cf-DNA %∆ (P = 0.002), CRP %∆ (P = 0.002), CK %∆ (P = 0.002) were all significantly higher than T1 at T2 and T3. In G2, CRP %∆ (P = 0.039) was significantly higher at T2 than T1. Despite the lack of statistically significant differences across all three testing times, cf-DNA %∆, CRP %∆ and CK %∆ increased throughout the season in G1. In G2, cf-DNA %∆, CRP %∆ and CK %∆ were all higher at T2 and T3 than T1 but fewer significant differences were present. This may suggest that cf-DNA is a useful marker to reflect accumulated soccer training and competitive stressors.

The purpose of this study was to investigate how maximal power output (P[subscript max]), as measured via the inertial load technique, changes throughout a collegiate soccer season in relation to training load completed. Furthermore, this study also aimed to describe the time course of recovery of [maximal power output] following two collegiate soccer matches in one weekend. The current investigation involved two experimental periods. The first took place throughout the 2010 Big XII soccer season. Nineteen Division I female collegiate soccer players (19.9 ± 1.2 yrs, 165.1 ± 6.6 cm, 61.0 ± 6.8 kg) from the same collegiate soccer team completed regular inertial load testing and perceptual fatigue questionnaires throughout this study period. These athletes' training was not altered in any way by the investigators throughout the 2010 season. During the second experimental period, two off-season matches were played in one weekend during the 2011 off-season. Training was prescribed by coaches, with the aim of simulating an in-season training week. [Maximal power output] and perceptual fatigue responses were monitored every day throughout the second study period. All training and matches throughout the study were monitored via the session RPE method. The results demonstrated that STARTERS experience much greater load throughout the season than NON-STARTERS (p<0.05, 2247 ± 176 AU and 1585 ± 174 AU), accounted for by increased load experienced during matches. This increased training load throughout the season lead to a decline in [maximal power output] in STARTERS (to 92.3 ± 6%, p<0.05) whilst [maximal power output] was maintained in NON-STARTERS (p>0.05) for the duration of the season. Furthermore, STARTERS experienced greater muscle soreness throughout the in-season period compared to NON-STARTERS. During the second experimental period [maximal power output] declined (p<0.05, 93.3 ± 7%) two days following matches played on the weekend and remained reduced for three days. Notably, two heavy training days in the middle of the training week appeared to have detrimental effects on both [maximal power output] and perceptual fatigue responses. The main finding of this study is that [maximal power output] declined throughout the middle and latter parts of the season in STARTERS, after experiencing significantly greater training loads than NON-STARTERS throughout the season. The current findings, combined with previous investigations, suggest that the inertial load technique may be useful in monitoring fatigue in team sport athletes. / text

Introduction: College soccer begins in August and ends in November, allowing athletes less than 4 months to condition and play all regular season matches. A consistent consequence of this condensed season structure is an elevated risk of training distress. In turn, training distress can lead to impaired performance and an increased likelihood of injury. Thus, it is important to identify signs of symptoms of distress early so that appropriate adjustments to training volume can be made. Simple, noninvasive techniques, which can be implemented by coaching staff, are ideal. This study investigated whether heart rate recovery was effective as an indicator of training distress in collegiate soccer players. Methods: 26 women and 17 men were enrolled in the study. Data were collected at 4 time points, measuring shuttle run time, heart rate recovery time, resting heart rate values, and MTDS questionnaire score. Heart rate recovery time was defined as the duration it took an athlete to reach 60% heart rate maximum from peak heart rate following the shuttle run. Results: Shuttle run times were prolonged in the beginning and end of season compared to the two mid-season tests (p < 0.001); heart rate recovery times differed at each time period (p=0.003); freshmen deviation from baseline was greater compared to all other grades (p=0.001). Although not statistically significant, resting heart rate values trended up at the end of the season for both genders. Conclusions: Heart rate recovery did not detect training distress in athletes; shuttle run times and resting heart rate appeared to be possible variables that should be taken in to consideration for further research and possibly assist in tailoring training session for optimal performance.