The aim of this study was to determine whether consumption of a diet containing 8.5 g carbohydrate (CHO) x kg(-1) x day(-1) (high CHO; HCHO) compared with 5.4 g CHO x kg(-1) x day(-1) (control; Con) during a period of intensified training (IT) would result in better maintenance of physical performance and mood state. In a randomized cross-over design, seven trained runners [maximal O(2) uptake (Vo(2 max)) 64.7 +/- 2.6 ml x kg(-1) x min(-1)] performed two 11-day trials consuming either the Con or the HCHO diet. The last week of both trials consisted of IT. Performance was measured with a preloaded 8-km all-out run on the treadmill and 16-km all-out runs outdoors. Substrate utilization was measured using indirect calorimetry and continuous [U-(13)C]glucose infusion during 30 min of running at 58 and 77% Vo(2 max). Time to complete 8 km was negatively affected by the IT: time significantly increased by 61 +/- 23 and 155 +/- 38 s in the HCHO and Con trials, respectively. The 16-km times were significantly increased (by 8.2 +/- 2.1%) during the Con trial only. The Daily Analysis of Life Demands of Athletes questionnaire showed significant deterioration in mood states in both trials, whereas deterioration in global mood scores, as assessed with the Profile of Mood States, was more pronounced in the Con trial. Scores for fatigue were significantly higher in the Con compared with the HCHO trial. CHO oxidation decreased significantly from 1.7 +/- 0.2 to 1.2 +/- 0.2 g/min over the course of the Con trial, which was completely accounted for by a decrease in muscle glycogen oxidation. These findings indicate that an increase in dietary CHO content from 5.4 to 8.5 g CHO x kg(-1)x day(-1) (41 vs. 65% total energy intake, respectively) allowed better maintenance of physical performance and mood state over the course of training, thereby reducing the symptoms of overreaching.

0158 PURPOSE: Gender differences have been reported in glycogen breakdown during exercise that could potentially affect resistance to over-reaching (defined as decreased performance and altered mood state) with repeated bouts of intense exercise. The aim of this study was to investigate whether gender differences exist in resistance to over-reaching during a period of intensified training (IT). METHODS: The training of 6 male (m) and 6 female (f) trained cyclists (VO2max m:68.6±6.8; f:65.2±4.0 ml/kg FFM/min; (mean±SE)) was intensified for 7 days. During the 11-day experiment, subjects received a diet containing 8g CHO/kg FFM/d (m:51±2 E%; f:52±5 E% CHO) and 15 E% protein. At the beginning and end of the IT, subjects performed a VO2maxtest and 60-min of cycling at 90% lactate threshold (m:70±5%, f:71±5%VO2max) followed by a time-trial (TT). Mood state was assessed by POMS and DALDA questionnaires. Substrate utilisation was measured using indirect calorimetry and a primed continuous [6,6 H2]-glucose infusion. RESULTS: No time × gender interaction effect was detected for maximal workload (Wmax), TT performance or total mood score. Wmax and TT performance decreased to a similar extent in both genders over the course of the study (m:7±3% vs f:9±4% NS, and m:12±5% vs f:12±9% NS, resp). Total mood score increased significantly in the men (99±7 v 117±10, P<0.05) and women (111±8 v 120±4, P<0.05), but the changes did not differ between groups (NS). Total CHO oxidation decreased significantly after IT in the men (40±8 vs 23±7 mg/kg FFM/min, P<0.05), while it remained similar in the women (29±11 vs 26±10 mg/kg FFM/min, NS). The change in total CHO oxidation over the course of IT was significantly different between genders (P<0.05). Before the IT, muscle glycogen oxidation contributed significantly more to energy expenditure in the men (60±8%) compared to the women (40±15%; P<0.05). This difference disappeared after the IT (m:33±10%; f:33±13%). No differences in Ra or Rd glucose at rest and during exercise were found between genders, both before and at the end of the IT. CONCLUSIONS: In the present study, there were no differences in performance decrement or mood state alteration between men and women after a period of intensified training. Furthermore, gender differences in substrate selection disappeared after a period of intensified training. This work was funded by the Human Sciences Domain of the UK Ministry of Defence scientific Research Programme

PURPOSE The aim of this study was to determine if a high-carbohydrate (HCHO) compared to a control (CON) diet during a period of intensified training would prevent the development of overreaching. METHODS In a randomized cross-over design, the training of 7 trained male runners (VO2max 64.7 ± 2.6 ml/kg/min) was intensified for 7 days, after 4 days of normal training. On three days, subjects ran 60min steady state on a treadmill followed by a self-paced 8km all out run and on four days they ran 16km all out. During the two trials they consumed either a HCHO (8.5 ± 0.2 g CHO/kg/d) or a CON-diet (5.4 ± 0.1 g CHO/kg/d). Substrate utilization was measured using indirect calorimetry on day 1 and 11 and glucose kinetics were studied using a primed continuous [U-13C]-glucose infusion during 30 min of running at 58% VO2max and 30 min at 77% VO2max on day 11. RESULTS Time to complete 8km was significantly increased by 61 ± 23s in the HCHO-trial and by 155 ± 38s in the CON-trial. The 16km times were only significantly increased during the CON diet (8.2 ± 2.1%). Increases in global mood scores as assessed with the POMS were more marked in the CON-trial than the HCHO-trial. Training resulted in 7 ± 2 and 13 ± 2 fold increases in fatigue scores during the HCHO and CON-trials resp. During exercise at 58% VO2max, CHO oxidation decreased significantly from 1.7 ± 0.2 to 1.2 ± 0.2 g/min over the course of the CON-trial, while no changes were seen in the HCHO trial. On day 11, muscle glycogen oxidation was significantly higher during the HCHO trial compared to the CON trial at 58% VO2max (1.7 ± 0.2 vs 1.0 ± 0.1 g/min) and at 77% VO2max (2.2 ± 0.2 vs 1.2 ± 0.2 g/min). CONCLUSION The decrease in CHO oxidation during 7 days of CON was completely accounted for by a decrease in muscle glycogen oxidation. The findings indicate that during a period of intensified running training consuming a HCHO diet compared to a CON diet reduces the symptoms of overreaching, but it cannot prevent it. Supported by a grant of the Chemical Biological Defence and Human Sciences Domain of the UK MOD's CRP

PURPOSE:Chronic exertional compartment syndrome (CECS) in the anterior tibial (AT) compartment is generally believed to be the result of reduced venous blood flow caused by restrictive compartments and increased intramuscular pressures. If this is so, then restricting venous flow in the muscles of healthy subjects during exercise should mimic CECS. METHODS:This hypothesis was tested in 10 control subjects (aged 19-41 yr, five males) with and without external venous occlusion induced by a sphygmomanometer cuff fitted just below the knee and inflated to 80 mm Hg. Twenty CECS patients (20-39 yr, 16 males) were studied without external occlusion. Subjects performed intermittent, isometric maximal voluntary contractions (MVC) of the AT for 20 min (1.6-s contractions, 0.5 duty cycle). MVC, tetanic force (2 s at 50 Hz), muscle thickness (ultrasound imaging), and pain were measured during exercise and 10 min of recovery. RESULTS:Venous occlusion in the controls induced greater pain, fatigue, and increase in muscle thickness (P < 0.01). Initially the patients fatigued more slowly than the occluded controls, but at the end of exercise, the fatigue and pain were similar in these two groups. The controls showed a greater increase in muscle size (P = 0.01). Recovery was similar in all three groups, although the size of the patients' muscles recovered rather more slowly. CONCLUSION:External venous occlusion of the AT muscles in control subjects induces changes very similar to those of CECS patients, although the different time courses indicate that different processes are involved. The AT compartment of CECS patients is capable of distension.