The purpose of this study was to evaluate the postactivation potentiation (PAP) effect of isometric and plyometric contractions on explosive performance of the upper and the lower limbs in male and female elite athletes. Thirteen male and ten female international level fencers performed four protocols of either isometric (3 sets of 3 sec) or plyometric (3 sets of 5 repetitions) bench and leg press, in a within subject randomized design. Before and immediately after the PAP treatment and following 4, 8, 12 min, explosive performance was measured by performing a countermovement jump (CMJ) or a bench press throw. Statistical analysis revealed significant time effect for peak leg power during the CMJ (p < 0.001) only for men, with values after the isometric PAP treatment being lower than baseline at the 8 and 12 min time points (by 7.5% (CI95% = 3.9-11.2%) and 8.7% (CI95% = 6.0-11.5%, respectively), while after the plyometric PAP treatment peak leg power remained unchanged. A significant negative correlation was found between leg strength (as expressed by 1-RM leg press performance) and the change in peak leg power between baseline and after 12 min of recovery only in male fencers (r = -0.55, p < 0.05), suggesting that stronger individuals may show a greater decrease in peak leg power. Based on the above results we conclude that lower body power performance in international level fencers may be negatively affected after isometric contractions and thus they should be advised against using isometric exercises to induce PAP with the protocol prescribed in the present study. Furthermore, gender and strength level must be considered in the practical application of PAP. © Journal of Sports Science and Medicine.

Repeated-sprint training often involves short sprints separated by inadequate recovery intervals. The effects of interval duration on metabolic and performance parameters are unclear. We compared the effects of two training programmes, differing in rest interval duration, on muscle (vastus lateralis) metabolism and sprint performance. Sixteen men trained three times a week for 8 weeks, each training session comprising 2-3 sets of two 80-m sprints. Sprints were separated by 10 s (n = 8) or 1 min (n = 8). Both training programmes improved performance in the 100-, 200-, and 300-m sprints, but the improvement was greater in the 10-s group during the final 100 m of the 200- and 300-m runs. Independent of interval duration, training mitigated the drop of muscle ATP after two 80-m sprints. The drop in phosphocreatine and the increases in glucose-6-phosphate and fructose-6-phosphate after two 80-m sprints were greater in the 10-s group. In conclusion, training with a limited number of repeated short sprints (≤10 s) may be more effective in improving speed maintenance in 200- and 300-m runs when performed with a 1:1 rather than a 1:6 exercise-to-rest ratio. This may be due to a greater activation of glycolysis caused, in part, by the limited resynthesis of phosphocreatine during the very short rest interval. © 2011 Taylor & Francis.

The aim of the present study was to evaluate the levels of homocysteine and 8-iso PGF2a in football and hockey players before and soon after a match, on the predisposition for development of atherosclerosis. We measured 8-iso-PGF2a and homocysteine in 21 football athletes aged 21.8 ± 3.7 years old and 18 hockey athletes 22.2 ± 3.3 years old, respectively. All the athletes presented significant increases in serum homocysteine levels following the match (p = 0.001 for football and p = 0.001 for hockey players) Also a statistically significant increase of 8-iso-PGF 2a levels was found in hockey and football athletes following the match (p < 0.001 and p = 0.071). Our findings suggest that strenuous exercise such as a football or a hockey match causes a marked increase in serum homocysteine and 8-iso-PGF2a. Due to the fact that homocysteine and 8-iso-PGF2a are contributing to atheromatosis, it may be useful to follow a restoration exercise program that involves mild exercise and to pay special attention to folate, vitamin B6, and vitamin B12 balance during the first 24 h after the match. Copyright © Taylor & Francis Group, LLC.

This study compared the effects of two different half-squat training programs on the repeated-sprint ability of soccer players during the preseason. Twenty male professional soccer players were divided into 2 groups: One group (S-group) performed 4 sets of 5 repetitions with 90% of their 1-repetition maximum (1RM), and the other group (H-group) performed 4 sets of 12 repetitions with 70% of 1RM, 3 times per week for 6 weeks, in addition to their common preseason training program. Repeated-sprint ability was assessed before and after training by 10 × 6-second cycle ergometer sprints separated by 24 seconds of passive recovery. Maximal halfsquat strength increased significantly in both groups (p < 0.01), but this increase was significantly greater in the S-group compared with the H-group (17.3 ± 1.9 vs. 11.0 ± 1.9%, p < 0.05). Lean leg volume (LLV) increased only in the H-group. Total work over the 10 sprints improved in both groups after training, but this increase was significantly greater in the second half (8.9 ± 2.6%) compared with the first half of the sprint test (3.2 ± 1.7%) only in the S-group. Mean power output (MPO) expressed per liter of LLV was better maintained during the last 6 sprints posttraining only in the S-group, whereas there was no change in MPO per LLV in the H-group over the 10 sprints. These results suggest that resistance training with high loads is superior to a moderate-load program, because it increases strength without a change in muscle mass and also results in a greater improvement in repeated sprint ability. Therefore, resistance training with high loads may be preferable when the aim is to improve maximal strength and fatigue during sprinting in professional soccer players. © 2011 National Strength and Conditioning Association.

The aim of the present study was to evaluate the levels of homocysteine and 8-iso PGF2a in football and hockey players before and soon after a match, on the predisposition for development of atherosclerosis. We measured 8-iso-PGF2a and homocysteine in 21 football athletes aged 21.8 ± 3.7 years old and 18 hockey athletes 22.2 ± 3.3 years old, respectively. All the athletes presented significant increases in serum homocysteine levels following the match (p = 0.001 for football and p = 0.001 for hockey players) Also a statistically significant increase of 8-iso-PGF 2a levels was found in hockey and football athletes following the match (p < 0.001 and p = 0.071). Our findings suggest that strenuous exercise such as a football or a hockey match causes a marked increase in serum homocysteine and 8-iso-PGF2a. Due to the fact that homocysteine and 8-iso-PGF2a are contributing to atheromatosis, it may be useful to follow a restoration exercise program that involves mild exercise and to pay special attention to folate, vitamin B6, and vitamin B12 balance during the first 24 h after the match. Copyright © Taylor & Francis Group, LLC.

This study compared the effects of two different half-squat training programs on the repeated-sprint ability of soccer players during the preseason. Twenty male professional soccer players were divided into 2 groups: One group (S-group) performed 4 sets of 5 repetitions with 90% of their 1-repetition maximum (1RM), and the other group (H-group) performed 4 sets of 12 repetitions with 70% of 1RM, 3 times per week for 6 weeks, in addition to their common preseason training program. Repeated-sprint ability was assessed before and after training by 10 × 6-second cycle ergometer sprints separated by 24 seconds of passive recovery. Maximal halfsquat strength increased significantly in both groups (p < 0.01), but this increase was significantly greater in the S-group compared with the H-group (17.3 ± 1.9 vs. 11.0 ± 1.9%, p < 0.05). Lean leg volume (LLV) increased only in the H-group. Total work over the 10 sprints improved in both groups after training, but this increase was significantly greater in the second half (8.9 ± 2.6%) compared with the first half of the sprint test (3.2 ± 1.7%) only in the S-group. Mean power output (MPO) expressed per liter of LLV was better maintained during the last 6 sprints posttraining only in the S-group, whereas there was no change in MPO per LLV in the H-group over the 10 sprints. These results suggest that resistance training with high loads is superior to a moderate-load program, because it increases strength without a change in muscle mass and also results in a greater improvement in repeated sprint ability. Therefore, resistance training with high loads may be preferable when the aim is to improve maximal strength and fatigue during sprinting in professional soccer players. © 2011 National Strength and Conditioning Association.

The purpose of this study was to evaluate the postactivation potentiation (PAP) effect of isometric and plyometric contractions on explosive performance of the upper and the lower limbs in male and female elite athletes. Thirteen male and ten female international level fencers performed four protocols of either isometric (3 sets of 3 sec) or plyometric (3 sets of 5 repetitions) bench and leg press, in a within subject randomized design. Before and immediately after the PAP treatment and following 4, 8, 12 min, explosive performance was measured by performing a countermovement jump (CMJ) or a bench press throw. Statistical analysis revealed significant time effect for peak leg power during the CMJ (p < 0.001) only for men, with values after the isometric PAP treatment being lower than baseline at the 8 and 12 min time points (by 7.5% (CI95% = 3.9-11.2%) and 8.7% (CI95% = 6.0-11.5%, respectively), while after the plyometric PAP treatment peak leg power remained unchanged. A significant negative correlation was found between leg strength (as expressed by 1-RM leg press performance) and the change in peak leg power between baseline and after 12 min of recovery only in male fencers (r = -0.55, p < 0.05), suggesting that stronger individuals may show a greater decrease in peak leg power. Based on the above results we conclude that lower body power performance in international level fencers may be negatively affected after isometric contractions and thus they should be advised against using isometric exercises to induce PAP with the protocol prescribed in the present study. Furthermore, gender and strength level must be considered in the practical application of PAP. © Journal of Sports Science and Medicine.

Repeated-sprint training often involves short sprints separated by inadequate recovery intervals. The effects of interval duration on metabolic and performance parameters are unclear. We compared the effects of two training programmes, differing in rest interval duration, on muscle (vastus lateralis) metabolism and sprint performance. Sixteen men trained three times a week for 8 weeks, each training session comprising 2-3 sets of two 80-m sprints. Sprints were separated by 10 s (n = 8) or 1 min (n = 8). Both training programmes improved performance in the 100-, 200-, and 300-m sprints, but the improvement was greater in the 10-s group during the final 100 m of the 200- and 300-m runs. Independent of interval duration, training mitigated the drop of muscle ATP after two 80-m sprints. The drop in phosphocreatine and the increases in glucose-6-phosphate and fructose-6-phosphate after two 80-m sprints were greater in the 10-s group. In conclusion, training with a limited number of repeated short sprints (≤10 s) may be more effective in improving speed maintenance in 200- and 300-m runs when performed with a 1:1 rather than a 1:6 exercise-to-rest ratio. This may be due to a greater activation of glycolysis caused, in part, by the limited resynthesis of phosphocreatine during the very short rest interval. © 2011 Taylor & Francis.

The aim of the present study was to evaluate the levels of homocysteine and 8-iso PGF 2a in football and hockey players before and soon after a match, on the predisposition for development of atherosclerosis. We measured 8-iso-PGF 2a and homocysteine in 21 football athletes aged 21.8 ± 3.7 years old and 18 hockey athletes 22.2 ± 3.3 years old, respectively. All the athletes presented significant increases in serum homocysteine levels following the match (p = 0.001 for football and p = 0.001 for hockey players) Also a statistically significant increase of 8-iso-PGF 2a levels was found in hockey and football athletes following the match (p < 0.001 and p = 0.071). Our findings suggest that strenuous exercise such as a football or a hockey match causes a marked increase in serum homocysteine and 8-iso-PGF 2a. Due to the fact that homocysteine and 8-iso-PGF 2a are contributing to atheromatosis, it may be useful to follow a restoration exercise program that involves mild exercise and to pay special attention to folate, vitamin B6, and vitamin B12 balance during the first 24 h after the match. Copyright © Taylor & Francis Group, LLC.

This study compared the effects of two different half-squat training programs on the repeated-sprint ability of soccer players during the preseason. Twenty male professional soccer players were divided into 2 groups: One group (S-group) performed 4 sets of 5 repetitions with 90% of their 1-repetition maximum (1RM), and the other group (H-group) performed 4 sets of 12 repetitions with 70% of 1RM, 3 times per week for 6 weeks, in addition to their common preseason training program. Repeated-sprint ability was assessed before and after training by 10 × 6-second cycle ergometer sprints separated by 24 seconds of passive recovery. Maximal halfsquat strength increased significantly in both groups (p < 0.01), but this increase was significantly greater in the S-group compared with the H-group (17.3 ± 1.9 vs. 11.0 ± 1.9%, p < 0.05). Lean leg volume (LLV) increased only in the H-group. Total work over the 10 sprints improved in both groups after training, but this increase was significantly greater in the second half (8.9 ± 2.6%) compared with the first half of the sprint test (3.2 ± 1.7%) only in the S-group. Mean power output (MPO) expressed per liter of LLV was better maintained during the last 6 sprints posttraining only in the S-group, whereas there was no change in MPO per LLV in the H-group over the 10 sprints. These results suggest that resistance training with high loads is superior to a moderate-load program, because it increases strength without a change in muscle mass and also results in a greater improvement in repeated sprint ability. Therefore, resistance training with high loads may be preferable when the aim is to improve maximal strength and fatigue during sprinting in professional soccer players. © 2011 National Strength and Conditioning Association.

The purpose of this study was to evaluate the postactivation potentiation (PAP) effect of isometric and plyometric contractions on explosive performance of the upper and the lower limbs in male and female elite athletes. Thirteen male and ten female international level fencers performed four protocols of either isometric (3 sets of 3 sec) or plyometric (3 sets of 5 repetitions) bench and leg press, in a within subject randomized design. Before and immediately after the PAP treatment and following 4, 8, 12 min, explosive performance was measured by performing a countermovement jump (CMJ) or a bench press throw. Statistical analysis revealed significant time effect for peak leg power during the CMJ (p < 0.001) only for men, with values after the isometric PAP treatment being lower than baseline at the 8 and 12 min time points (by 7.5% (CI95% = 3.9-11.2%) and 8.7% (CI95% = 6.0-11.5%, respectively), while after the plyometric PAP treatment peak leg power remained unchanged. A significant negative correlation was found between leg strength (as expressed by 1-RM leg press performance) and the change in peak leg power between baseline and after 12 min of recovery only in male fencers (r = -0.55, p < 0.05), suggesting that stronger individuals may show a greater decrease in peak leg power. Based on the above results we conclude that lower body power performance in international level fencers may be negatively affected after isometric contractions and thus they should be advised against using isometric exercises to induce PAP with the protocol prescribed in the present study. Furthermore, gender and strength level must be considered in the practical application of PAP. © Journal of Sports Science and Medicine.

Repeated-sprint training often involves short sprints separated by inadequate recovery intervals. The effects of interval duration on metabolic and performance parameters are unclear. We compared the effects of two training programmes, differing in rest interval duration, on muscle (vastus lateralis) metabolism and sprint performance. Sixteen men trained three times a week for 8 weeks, each training session comprising 2-3 sets of two 80-m sprints. Sprints were separated by 10 s (n = 8) or 1 min (n = 8). Both training programmes improved performance in the 100-, 200-, and 300-m sprints, but the improvement was greater in the 10-s group during the final 100 m of the 200- and 300-m runs. Independent of interval duration, training mitigated the drop of muscle ATP after two 80-m sprints. The drop in phosphocreatine and the increases in glucose-6-phosphate and fructose-6-phosphate after two 80-m sprints were greater in the 10-s group. In conclusion, training with a limited number of repeated short sprints (≤10 s) may be more effective in improving speed maintenance in 200- and 300-m runs when performed with a 1:1 rather than a 1:6 exercise-to-rest ratio. This may be due to a greater activation of glycolysis caused, in part, by the limited resynthesis of phosphocreatine during the very short rest interval. © 2011 Taylor & Francis.