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The purpose of the present study was to investigate the acute effect of drop jumping on throwing performance. Eight men and 8 women, moderately trained subjects with basic shot put skills, performed 3 squat underhand front shot throws after a short standard warm-up. Three minutes later they performed 5 maximal consecutive drop jumps from 40 cm. Immediately after the drop jumps, they repeated the squat underhand front shot throws. On another day, their 6 repetition maximum (RM) muscular strength in leg press was assessed. Muscle biopsies were also obtained from vastus lateralis for the determination of fiber-type composition and fiber cross-sectional area. Throwing performance was significantly increased after drop jumping (8.25 [+ or -] 1.1 m vs. 8.63 [+ or -] 1.3 m, p < 0.01). The percentage of type II muscle fiber area was significantly related to the increase in throwing performance after drop jumping (r = 0.76, p < 0.01). The increase in throwing performance was significant in men (8.94 [+ or -] 1 m vs. 9.60 [+ or -] 0.9 m, p < 0.01 ) but not in women (7.56 [+ or -] 1 m vs. 7.67 [+ or -] 0.9 m, ns). Of note, the percentage of type II fiber area was higher in men than in women (M: 66.4 [+ or -] 13%, F: 50.2 [+ or -] 15%, p < 0.01 ). Leg press strength (6RM) was moderately related to the increase in throwing performance after drop jumping (r = 0.50, p < 0.05). These results suggest that drop jumping just before a throwing action induces an increase in performance in subjects with a high percentage of type II muscle fiber area and (to a lesser degree) in subjects with enhanced muscular strength. KEY WORDS fiber-type composition, postactivation potentiation, warm-up, shot put

The aim of this study was to investigate changes in shot put performance, muscular power, and neuromuscular activation of the lower extremities, between the preseason and the competition period, in skilled shot put athletes using the rotational technique. Shot put performance was assessed at the start of the pre-season period as well as after 12 weeks, at the competition period, in nine shot putters. Electromyographic (EMG) activity of the right vastus lateralis muscle was recorded during all shot put trials. Maximum squat strength (1RM) and mechanical parameters during the countermovement jump (CMJ) on a force platform were also determined at pre-season and at competition period. Shot put performance increased 4.7% (p < 0.05), while 1RM squat increased 6.5% (p < 0.025). EMG activity during the delivery phase was increased significantly (p < 0.025) after the training period. Shot put performance was significantly related with muscular power and takeoff velocity during the CMJ, at competition period (r = 0.66, p < 0.05 and 0.70, p < 0.05), but not with maximum vertical force. One RM squat was not related significantly with shot put performance. These results suggest that muscular power of the lower extremities is a better predictor of rotational shot put performance than absolute muscular strength in skilled athletes, at least during the competition period. KEY WORDS rotational shot put, electromyographic activity, countermovement jump

The purpose of the present study was to investigate the effect of short-term resistance training and detraining on shot put throwing performance. Eleven young healthy subjects with basic shot put skills participated in 14 weeks of resistance training, which was followed by 4 weeks of detraining. Shot put performance in four field tests was measured before (T1) and after (T2) resistance training and after detraining (T3). At the same time points, one repetition maximum (1RM) was measured in squat, bench press, and leg press. Fat-free mass (FFM) was determined with dual x-ray absorptiometry and muscle biopsies obtained from vastus lateralis for the determination of fiber type composition and cross-sectional area (CSA). 1RM strength increased 22-34% (p < 0.01) at T2 and decreased 4-5% (not significantly different) at T3. Shot put performance increased 6-12% (p < 0.05) after training and remained unaltered after detraining. FFM increased at T2 (p < 0.05) but remained unchanged between T2 and T3. Muscle fiber CSA increased 12-18% (p < 0.05) at T2. Type I muscle fiber CSA was not altered after detraining, but type Ila and IIx fiber CSA was reduced 10-12% (p < 0.05). The percentage of type IIx muscle fibers was reduced after training (T1 = 18.7 [+ or -] 4, T2 = 10.4 [+ or -] 1; p < 0.05), and it was increased at T3 compared with T2 (T3 = 13.7 [+ or -] 1; p < 0.05). These results suggest that shot put performance remains unaltered after 4 weeks of complete detraining in moderately resistance-trained subjects. This might be linked to the concomitant reduction of muscle fiber CSA and increase in the percentage of type IIx muscle fibers. KEY WORDS fiber type composition, fiber cross-sectional area, fat-free mass, shot put

The purpose of this study was to investigate the relationship between skeletal muscle fiber type composition and the maximum number of repetitions performed during submaximal resistance exercise. Twelve young men performed a maximum repetitions test at 85% of 1 repetition maximum (1RM) in the leg press, which was repeated after 1 week. Seven days after the second 85% 1 RM test, they performed a maximum repetitions test at 70% of 1RM in the leg press. This test, at 70% 1RM, was repeated 7 days later. One week before the initiation of the testing sessions, a biopsy sample was obtained from the vastus lateralis muscle and analyzed for fiber type distribution, fiber cross-sectional area, and capillary density (capillaries*[mm.sup.-2]). A low and nonsignificant relationship was found between the fiber type distribution or percent fiber type area and the number of repetitions performed at either 70% or 85% 1 RM. Moreover, the number of repetitions performed at 70% or 85% of 1 RM was not related significantly with 1 RM strength. In contrast, the number of repetitions performed at 70% 1RM was significantly correlated with the number of capillaries per [mm.sup.2] of muscle cross-sectional area (r = 0.70; p = 0.01). These results suggest that fiber type composition is not the major biological variable regulating the number of repetitions performed in submaximal resistance exercise. Rather, it seems that submaximal strength performance depends on muscle capillary density, which is linked with the endurance capacity of the muscle tissue. KEY WORDS skeletal muscle morphology, one repetition maximum, muscular endurance

A study was conducted to analyze the distribution of the lactate/H+ transporter isoforms, monocarboxylate transporter isoforms (MCT) 1 and MCT4, in the skeletal muscle. The quantification of the isoforms was performed with polyclonal antibodies raised to human MCT1 and MCT4 in rabbits. Results indicated that the content of MCT1 in a muscle varied between different muscles while fiber-type differences in MCT1 content were minor within a given muscle secretion.