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Method: Ten female international field hockey players gave informed consent to participate in the study. The mean (SD) age and mass of the players were 25.2 (4.0) years and 64.4 (6.4) kg respectively. Data were collected during a 5 day tournament (non ranking) period comprising: day 1-2, and 4-5 match days and day 3 recovery day. Fasted capillary blood samples were taken on all days. Plasma samples were analysed for immunoglobulin A (IgA), Creatine Kinase (CK), C-reactive protein (CRP) and Urea. Unstimulated saliva samples were taken for all days and analysed for testosterone, cortisol and testosterone/cortisol ratio (T/C ratio). A global positioning system was used to assess distance covered at particular speeds (‘standing’ 0-0.7; ‘walking’ 0.7-6.1; ‘jogging’ 6.1-11.2; ‘running’ 11.2-15.1; ‘fast running’ 15.1-19.1; ‘sprinting’ 19.1 km/h), intensities (‘low’ 0-6.1; ‘moderate’ 6.1-15.1; ‘high’ 15.1 km/h) and heart rate. Data was analysed using 1and 2-way ANOVA with repeated measures. Statistical Significance was set at P0.05.
Results: No differences were observed in the mean distance covered between games 1-4. As the tournament progressed no significant differences were observed in the distances covered in motion type or intensity. IgA was significantly lower on day 3 (1.46 (0.6) g/l, P=0.018) when compared to day 4, which corresponded to two consecutive matches (Day 1 and2) and a recovery day on day 3. CK increased from 116.0 (28.8) U/l at rest to 165.9 (42.8) U/l (P=0.026) after the second game, reduced below initial baseline following a recovery day and subsequently increased after the following game (181.7 (77.1) U/l; P0.001).
Conclusions: The repeated match play experienced in the present tournament did not result in any residual or accumulated fatigue. It is possible that a more demanding competitive schedule such as that experienced during the Olympic Games will have an effect of the activity patterns of players during later matches.
Sunderland, C., Stokes, K. & Morris, J. (2008) Performance, immune status and muscle damage during an international field hockey tournament. 13th Annual Congress of the European College of Sports Science. Estoril, Portugal.
THE EFFECT OF DELAYED ONSET OF MUSCLE SORENESS ON HABITUAL TRAPEZIUS ACTIVITYMORK, P.J., WAKEFIELD, E., HOLTERMANN, A.
NORWEGIAN UNIVERSITY OF SCIENCE AND TECHNOLOGY, TRONDHEIM, NORWAYIntroduction: The frequently cited pain adaption model (Lund et al 1991) predicts that muscle pain, acute or chronic, will cause inhibition of muscle activity to protect the muscle from further damage. The model is supported by laboratory studies but there is a lack of studies investigating the effect of muscle pain on habitual muscle activity during daily activities. The aim of the study was to investigate whether acute upper trapezius pain, caused by delayed onset of muscle soreness (DOMS), influences habitual trapezius activity.
Methods: Eleven right-handed female subjects (mean age 22 yrs, range 20-24 yrs) were recruited from a convenience sample of university students. Long-term (5 hrs) surface electromyographic (sEMG) activity was recorded (Myomonitor III, Delsys, US) bilaterally from the clavicular, descending, transverse, and ascending parts of trapezius on two consecutive weekdays. Inclinometers were used to record body posture (sitting, standing, walking) and bilateral upper arm movement synchronously with sEMG. Subject where instructed to maintain normal daily activities during recordings but to avoid vigorous physical activity. Immediately after the first field recording, muscle pain was induced to the left upper trapezius by eccentric shoulder depression exercise. Assessment of pressure pain threshold (PPT) at the start of the field recordings and hourly pain scores on visual analogue scale (VAS) during the field recordings was used to quantify trapezius pain.
Results: PPT decreased for the left medial, center, and lateral part of the upper trapezius (P0.004 for all comparisons) from day 1 to day
2. PPT remained unchanged in the lower left and right trapezius. VAS scores increased from day 1 to day 2 for the left upper trapezius (P0.004). The root-mean-square median sEMG level increased during seated posture for the left descending trapezius (P0.05). Trapezius activity remained unchanged in all other parts of the left trapezius and all parts of the right trapezius. Arm elevation, arm movement, and time with different body postures remained unchanged from first to second field recording.
Discussion: Trapezius pain (i.e., DOMS) was demonstrated by the reduced PPT at the three sites associated to the exercised upper part of the left trapezius and by the raised hourly VAS scores during the second long-term recording. An increased level of sEMG activity in the pain-afflicted descending part of the left trapezius was observed in periods with seated posture, i.e., situations with very low muscle activity or nominal muscle rest. These findings indicate that nociceptive input induces increased trapezius muscle tonus during periods with low biomechanical loading. Thus, the present study opposes the prediction of the pain adaption model.
References Lund JP, Donga R, Widmer CG, Stohler CS (1991). Can J Physiol Pharmacol, 69, 683-694.
THE EFFECTS OF EXERCISE-INDUCED MUSCLE DAMAGE ON CYCLING ENDURANCE PERFORMANCEBURT, D., TWIST, C.
UNIVERSITY OF CHESTERThe effects of exercise-induced muscle damage on cycling endurance performance Burt, D.G. & Twist, C.
University of Chester Introduction: The benefits of including resistance-based training for optimising endurance performance (Paavolainen et al., 1999) would suggest that endurance athletes engage more frequently in training that might cause symptoms of exercise-induced muscle damage (EIMD). Whilst, EIMD has been reported to impair muscle strength and power (Twist & Eston, 2007), the effects on endurance performance during ecologically valid settings have yet to be elucidated.
Method Following ethical approval, 17 participants were randomly assigned to either a treatment (n = 8) or control group (n = 9). Participants initially performed an incremental ramp protocol on a cycle ergometer to establish the workload corresponding to ventilatory threshold (VT). After a minimum of 24 h, participants performed a 5-minute fixed-intensity cycling at VT, followed by a 15-minute cycling time-trial.
Physiological, metabolic, and perceptual responses were measured during both fixed workload and time-trials. Perceived levels of muscle soreness and peak isokinetic knee extensor torque at 60 deg.s-1 were also recorded. Following 30 minutes rest from baseline measures, participants in the treatment group performed 10 x 10 plyometric jumps to induce symptoms of EIMD. After a further 48 h, measurements of perceived muscle soreness, peak isokinetic strength, and endurance performance during fixed-intensity and time-trial cycling were repeated.
Results: Significant interactions of time and group indicated increased muscle soreness and reduced knee extensor strength (P 0.05) for the treatment group following EIMD. No significant interactions of time and group on heart rate, RER, or blood lactate response were evident during the fixed-intensity exercise (P 0.05). However, VO2, VE, and RPE values were all significantly increased at VT in the treatment group at 48 h following EIMD (P 0.05). During the 15-minute time-trial, mean power output, distance covered, and VO2 during the time-trial were significantly lower in the treatment group at 48 h following EIMD (P 0.05). Moreover, there was no significant interaction of time and group for RPE (P0.05), suggesting that effort perception was unchanged during the time-trial in both groups following EIMD.
Discussion: We propose that the increased VE response was a sensory cue for the increased RPE during fixed-load exercise following EIMD. Furthermore, the increased VO2 following EIMD might have been evident to facilitate the rise in VE during fixed-intensity cycling.
EIMD also impairs time-trial cycling through altering the sense of effort. Athletes should be aware of performing muscle-damaging exercise in the days preceding competition.
References Paavolainen et al. (1999). J Appl Phsiol. 86: 1527-1533.
Twist, C. & Eston, R. (2007). J Exerc Sci Fit. 5: 1-9.
CHANGES IN THE RATE OF FORCE DEVELOPMENT MEASURED AT DIFFERENT MUSCLE LENGTHS FOLLOWING ECCENTRIC AND ISOMETRIC EXERCISEPHILIPPOU, A., BOGDANIS, G.C., MARIDAKI, M.
NATIONAL AND KAPODISTRIAN UNIVERSITY OF ATHENSIntroduction: The maximum rate of force development (RFD) has been shown to decrease after eccentric exercise (Crameri et al., 2007).
However, there is little information regarding the changes in RFD when it is assessed at different lengths of the exercised muscle (RFDlength relationship). Besides, although muscle damage can also occur after isometric contractions at a long muscle length (Philippou et al., 2003), it is not known whether RFD is similarly affected after this form of exercise. The aim of this study was to examine the effects of isometric exercise at long muscle length on RFD-length relationship and to compare them with those presented after eccentric exercise.
Methods Fourteen male volunteers, randomly divided into the eccentric (ECC, n=7) or the isometric (ISO, n=7) exercise group, performed 50 maximal voluntary eccentric, or isometric contractions at a long length of the elbow flexors of the non-dominant arm, on an isokinetic dynamometer. Peak isometric force (PIF) and time to peak force (TPIF) were measured at five different elbow angles, i.e., 50o, 70o, 90o, 140o, 160o, before and for 4 consecutive days post-exercise, and maximum RFD was determined as the PIF/TPIF ratio. Flexed (FANG) and relaxed (RANG) elbow angles and muscle soreness (DOMS) were also assessed at the same time points. Two-way ANOVA with repeated measures on one factor (day) was used for statistics.
Results: Both exercise protocols induced significant changes in the indirect markers of muscle damage post-exercise, i.e., DOMS, FANG and RANG, compared with baseline (P0.01). Maximum RFD before exercise was higher at the elbow angle of 140o compared with 50o and 70o (P0.001), while a similar RFD-length relationship was found in both groups. Maximum RFD was significantly decreased in both groups at all the angles tested in the days after the exercise regimens (P0.05-0.001). The percent changes in RFD (i.e., normalized to preexercise values) were also significant in each group over time (P0.05-0.001), but not between angles in any group or between groups.
Discussion: RFD-angle relationship was found to be similarly affected after both eccentric and isometric exercise at a long muscle length.
The decreased RFD following muscle damaging exercise has been attributed to changes in cytoskeletal integrity and to an increase in the compliance of some muscle fibers (McCully and Faulkner, 1985; Crameri et al., 2007). However, the similar decreases in RFD at various muscle lengths found in the present study imply that other factors such as neuromuscular disturbances following muscle damage (Sayers et al., 2000) may also play an important role.
References McCully KK, Faulkner JA. (1985). J Appl Physiol, l59, 119-126.
Philippou A, Maridaki M, Bogdanis GC. (2003). J Sports Sci, 21(10), 859-865.
Crameri RM, Aagaard P, Qvortrup K, Langberg H, Olesen J, Kjaer M. (2007). J Physiol, 583, 365-80.
Sayers SP, Clarkson PM, Lee J. (2000). Med Sci Sports Exerc, 32(9), 1587-1592.
14 ANNUAL CONGRESS OF THE EUROPEAN COLLEGE OF SPORT SCIENCETH Wednesday, June 24th, 2009
MRF RESPONSES IN THE ARM FLEXOR MUSCLES TO HIGH-FORCE ECCENTRIC EXERCISEHANSSEN, K.E., PAULSEN, G., DRANGE, M., KADI, F., RAASTAD, T.
NORWEGIAN SCHOOL OF SCIENCESIntroduction: High-force eccentric exercise may result in muscle damage involving myofibrillar disruptions and in some cases segmental fibre necrosis. The repair processes may involve activation of satellite cells leading to satellite cell proliferation and later differentiation and fusion with other satellite cells or damaged myofibers. After activation, the proliferation and later differentiation of satellite cells are driven by the myogenic regulatory factors (MRFs). Consequently, the expression of MRFs can be used as markers of myogenic events during the course of activation of satellite cells (1). The purpose of this study was to investigate the MRF responses in the arm flexors after unaccustomed eccentric exercise and to a repeated bout three weeks later. We hypothesized that in the exercised arm the MRF levels would increase after bout 1, but after bout 2 the increase would be attenuated do to less damage in the repeated bout.
Methods: Thirty-three young males and females (23-28 years) participated. Seventy unilateral voluntary maximal eccentric actions with the arm flexors were performed twice (bout 1 and 2) with the same arm, separated by three weeks. The participants were randomized into a test and a control group. The exercise was performed with the same arm, randomly chosen, on bout 1 and 2. The other arm served as a non-exercised control. Nine days after the exercise bouts, tests of the force-generation capacity were performed. Biopsies from m.
biceps brachii were collected from both exercised and control muscle 1, 48, 96, 168 hours after bout 1 and 1, 48 hours after bout 2. In order to visualize satellite cells cross sections were analyzed for immunoreactivity against CD56/NCAM (immunohistochemistry- IHC), and MRF protein content was determined using Western blotting.