Team handball is an Olympic sport that has rarely

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1 THE EFFECT OF HEAVY- VS. MODERATE-LOAD TRAINING ON THE DEVELOPMENT OF STRENGTH, POWER, AND THROWING BALL VELOCITY IN MALE HANDBALL PLAYERS SOUHAIL HERMASSI, 1 MOHAMED SOUHAIEL CHELLY, 1,2 MOURAD FATHLOUN, 3 AND ROY J. SHEPHARD 4 1 Research Unit Evaluation and Analysis of Factors Influencing Sport performance, Higher Institute of Sport and Physical Education of Ksar Said, Tunis, Tunisia; 2 Higher Institute of Sport and Physical Education of Ksar Said, Tunis, Tunisia; 3 Higher Institute of Sport and Physical Education, El Kef, Tunisia; and 4 Faculty of Physical Education & Health, University of Toronto, Toronto, Ontario, Canada ABSTRACT Hermassi, S, Chelly, MS, Fathloun, M, and Shephard, RJ. The effect of heavy- vs. moderate-load training on development of strength, power, and throwing ball velocity in male handball players. J Strength Cond Res 24(9): , 2010 The aim was to compare effect of 2 differing 10-week resistance training programs on peak power (PP) output, muscle volume, strength, and throwing velocity of upper limbs in handball players during competitive season. The subjects were 26 men (age years, body mass kg, height m, and body fat %). They were randomly assigned to 1 of 3 groups: control (C; n = 8), heavy resistance (n = 9), or moderate resistance (MR; n = 9) training, performed twice a week. A force velocity test on an appropriately modified Monark cycle ergometer determined PP. Muscle volumes were estimated using a standard anthropometric kit. One-repetition maximum (1RM) bench press (1RM BP ) and 1RM pull-over (1RM PO ) scores assessed arm strength. Handball throwing velocity was measured with (T R ) and without run-up (T W ). Both training programs enhanced absolute PP relative to controls (p, 0.05), although differences disappeared if PP was expressed per unit of muscle volume. Heavy resistance enhanced 1RM BP and 1RM PO compared to both MR (p, 0.01 and p, 0.05, respectively) and C (p, for both tests). Heavy resistance also increased T R and T W compared to C (p, 0.01 and p, 0.05, respectively). Moderate resistance increased only T R compared to C (p, 0.01). Thus, during competitive season, PP, 1RM BP, 1RM PO, and T W of male handball players were Address correspondence to Dr. Mohamed Souhaiel Chelly, csouhaiel@ yahoo.fr. 24(9)/ Ó 2010 National Strength and Conditioning Association increased more by 10 weeks of bench press and pull-over training with suitably adapted heavy loads than with moderate loads. It would seem advantageous to add such resistance exercise before customary technical and tactical handball training sessions. KEY WORDS arm throwing, maximal strength, upper extremity, throwing performance INTRODUCTION Team handball is an Olympic sport that has rarely been object of scientific investigation. Available research suggests that successful players have welldeveloped aerobic and anaerobic fitness (6,10,29). The physical demands are for running, jumping, sprinting, throwing, hitting, blocking, and pushing. The game requires high-impact intermittent exercise, with many lateral movements, jumps, and throws (10). Throwing is a fundamental skill. Two basic factors influence efficiency of shots: accuracy and throwing velocity. The faster ball is thrown, less time defenders have to save shot. Handball coaches and scientists seem agreed that main determinants of throwing velocity are technique, timing of movement in consecutive body segments, and strength and power of both upper and lower limbs (11). Each of se factors can be improved by training, particularly resistance programs designed to enhance strength and power in both upper and lower limbs. However, re is disagreement concerning type of overload that is most likely to enhance velocity. Training programs that produce greatest change in muscle cross-section typically involve loads of 70% 1 repetition maximum (1RM) (22), whereas programs designed to improve strength through enhanced neuronal coordination are typified by intensities of % 1RM (5,22). The use of moderate loads allows trainee to attain greater velocities and accelerations, with a potential for transfer to such activities as handball (5). Neverless, 2408

2 many studies have argued that heavy training (.80% 1RM) can not only enhance power and strength but can also enhance handball throwing velocity of upper limbs (10,22,34). In his brief review, Van Den Tillaar (34) summarized current knowledge on respective benefits of various handball-training programs (training with overweight balls, training with underweight balls, training with underweight and overweight balls, and general weight training). He concluded that no clear answer could as yet be given as to type of resistance training that was most effective in increasing throwing velocity. There was no consensus on optimal loading for developing maximal strength, power, and thus throwing velocity. Moreover, few published studies of programs intended to increase strength and throwing velocity in handball players have used only concentric exercises (10,13,18,24). However, most of actions required during play but especially throwing ball require a combination of eccentric and concentric contractions (a stretch-shortening cycle [SSC]). Use of SSC exercises seems important for enhancement of an individual s power. Because greater power outputs are developed, greater power adaptation is likely. Moreover, velocity and acceleration profiles of rebound movement simulate those that occur during throwing more closely than do movements seen with nonrebound exercise (in particular, y have a higher velocity and a longer period of acceleration) (5). Based on technical limitations and inconclusive nature of aforementioned studies, our aim was to compare increases of performance induced when heavy resistance (HR) or moderate resistance (MR) training was added to normal in-season regimen of experienced handball players. To incorporate prestretch inherent to handball into both types of training, we used a succession of eccentric concentric contractions. We hyposized that 10 weeks of eir HR or MR training performed twice a week would enhance handball throwing velocity, strength, and power in upper limbs relative to players continuing with ir normal in-season regimen, and we aimed to determine which of 2 programs would be most effective. METHODS Experimental Approach to Problem This study was designed to address question: How far does 10 weeks of HR or MR in-season training, performed twice per week, enhance performance of handball players? To examine question experimentally, a team of experienced players was divided randomly into 3 groups: HR (n = 9), MR(n = 9), and control (standard in-season regimen) (C; n = 8). All participants completed 2 familiarization trials in 2 weeks before definitive testing. Definitive measurements began 4 months into playing season; data were collected before start of enhanced training, and after completion of 10-week trial. On each occasion, protocol included a force velocity test to evaluate muscle power of upper limbs, a handball-throwing test, a 1RM bench press, pull-over, and detailed anthropometric measurements to assess volume of muscle in upper limbs. Testing sessions were carried out at same time of day, and under same experimental conditions, at least 3 days after most recent competition. Players maintained ir normal intake of food and fluids during trial. However, y abstained from physical exercise for 1 day before testing, drank no caffeine-containing beverages in 4 hours preceding testing, and ate no food for 2 hours before testing. Verbal encouragement ensured maximal effort throughout tests of muscle performance. Subjects All procedures were approved by Institutional Review Committee for ethical use of human subjects, according to current national laws and regulations. Participants gave written informed consent after receiving both a verbal and a written explanation of experimental design and its potential risks. Subjects were told that y were free to withdraw from trial without penalty at any time. Our investigation was focused on 26 elite male handball players (age years, body mass kg, height m, and body fat %), all drawn from a single team in top National Handball League. Their mean handball experience was years. Before study, all were examined by team physician, with a particular focus orthopedic and or conditions that might preclude resistance training, and all were found to be in good health. The 26 individuals were randomly assigned between 3 groups: HR (n =9),MR(n = 9), and control (standard inseason regimen) C(n = 8). These 3 groups were initially well matched in terms of ir physical characteristics (Table 1). Evaluation and Procedures This study was performed during a 10-week period from January to March. All subjects engaged in same training sessions, supervised by 2 team coaches, from beginning of competitive season (September) until end of current study (March). They thus continued handball training 3 4 times per week and played 1 official game per week. Practice training sessions lasted 90 minutes; usually, y emphasized skill activities at various intensities, offensive and defensive strategies, and 30 minutes of continuous play with only brief interruptions by coach. The controls maintained this normal frequency of training, and 2 experimental groups supplemented se sessions by specific resistance exercises. All subjects also engaged in weekly school physical education sessions; se lasted for 40 minutes and consisted mainly of ball games. All participants were tested before and after 10-week trial, using identical protocols; tests were completed in a fixed order over 2 consecutive days. Care was taken to ensure that those undertaking resistance training were tested 5 9 days after ir last strength training session to allow adequate recovery from acute effects of resistance training. VOLUME 24 NUMBER 9 SEPTEMBER

3 Pull-Over and Bench Press Training and Arm Performance TABLE 1. Participants physical characteristics.* Age (y) Body mass (kg) Height (m) % Body fat Experience (y) HR (n = 9) MR (n = 9) C(n = 8) *HR = heavy load resistance group; MR = moderate load resistance group; C = control group. Values are given as mean 6 SD. Testing Schedule The subjects were carefully familiarized with techniques of circuit training and lifting for 2 weeks before measurements and training began. They were also familiarized with 1RM test procedure, and a oretical maximal load was calculated for each subject. Testing was integrated into weekly training schedules. During definitive tests, a standardized battery of warm-up exercises was performed before maximal efforts. On first definitive test day, force velocity test was performed, followed by anthropometrical assessment, and finally 1RM pull-over (1RM PO ) was measured. During second definitive test day, 1RM bench press (1RM BP )was measured, and throwing velocities were determined with subjects standing at ir adapted chairs. Day 1 The Force Velocity Test. Force velocity measurements on legs were performed on a standard Monark cycle ergometer (model 894 E, Monark Exercise AB, Vansbro, Sweden). The instantaneous peak velocity was used to calculate maximal anaerobic power for each braking force. The maximal velocity (Vmax) was defined as greatest velocity attained without external loading. The peak power (PP) was defined as greatest power output calculated for different braking forces. The subject was judged to have attained braking force corresponding to his maximal anaerobic power if an additional load induced a decrease in power output. Parabolic relationships were obtained only if we observed a decline of PP over 2 successive braking forces. Arm tests were made using an appropriately modified version of same apparatus. The ergometer pedals were replaced by hand cranks, and saddle pillar was removed to avoid injuries. The modified ergometer was fixed to a metal support, bringing crankshaft to shoulder level. The unrestrained subject stood freely in front of ergometer, TABLE 2. Heavy resistance training program.* Exercises Session 1 Session 2 Session 3 Session 4 Session 5 Session 6 Bench press 80: : : : : : Pull-over 80: : : : : : Exercises Session 7 Session 8 Session 9 Session 10 Session 11 Session 12 Bench press 90: : : : : : Pull-over 90: : : : : : Exercises Session 13 Session 14 Session 15 Session 16 Session 17 Session 18 Bench press 95: : : : : : Pull-over 95: : : : : : Exercises Session 19 Session 20 Bench press 95: : Pull-over 95: : Training summary Principal exercises % of RM sets 3 reps *RM = repetition maximum. 2410

4 TABLE 3. Moderate resistance training program.* Exercises Session1 Session2 Session3 Session4 Session5 Session6 Bench press 55: : : : : : Pull-over 55: : : : : : Exercises Session 7 Session 8 Session 9 Session 10 Session 11 Session 12 Bench press 65: : : : : : Pull-over 65: : : : : : Exercises Session 13 Session 14 Session 15 Session 16 Session 17 Session 18 Bench press 70: : : : : : Pull-over 70: : : : : : Exercises Session 19 Session 20 Bench press 75: : Pull-over 75: : Training summary Principal exercises % of RM Sets 3 reps *RM = repetition maximum. with exception that smallest subjects were allowed to stand on a step as needed. This posture was adopted to minimize activation of lower limbs during test performance. The parameters measured with force velocity test were PP expressed in W and Wkg 21 of total body mass, maximal force (Fmax), and maximal velocity (Vmax). The relationship between braking force F and velocity V can be expressed by following equation: V ¼ b af or V ¼ V 0 V 0 F =F 0 ¼ V 0 ð1 F =F 0 Þ; where V 0 is intercept with velocity axis, that is, oretical maximal velocity for a braking force of zero, and F 0 is intercept with force axis, that is, oretical maximal braking force corresponding to a velocity of zero (36). A valid force velocity test requires short all-out sprints (duration about 7 seconds), using a suitable sequence of ergometer braking forces (1). Subjects were verbally encouraged to reach ir maximal pedaling rate as quickly as possible. The peak velocity was noted and was used to calculate force velocity relationships. Arm tests began with a braking force = 1.5% of subject s body mass (3). After a 5-minute recovery, braking was increased in sequence to 2, 3, 4, 5, 6, 7, 8, and 9% of body mass. The same sequence was performed again, until an additional load induced a decrease in power output at each of 2 repetitions; this value was accepted as PP. In general, 6 8 short all-out sprints were performed in a given session. TABLE 4. Comparison of handball throwing velocity between HR, MR, and C before and after 10-week trial.* HR MR C Pre Post Pre Post Pre Post T R (ms 21 ) k T W (ms 21 ) *HR = heavy resistance group; MR = moderate resistance; C = control group; T R = handball throwing velocity with run-up; T W = handball throwing velocity without upper limb run-up. Values are given as mean 6 SD. Two-way analysis of variance with repeated measure (group 3 time) was used to assess training related effects. MR significantly different from C at p, k HR significantly different from C at p, VOLUME 24 NUMBER 9 SEPTEMBER

5 Pull-Over and Bench Press Training and Arm Performance Anthropometry. The muscle volume of upper limbs was estimated as detailed previously, using circumferences and skin-fold thicknesses measured at different levels of arm and forearm, length of upper limb, and breadth of humeral condyles (20,32,33). Muscle volumes were estimated as follows: Muscle volume ¼ total limb volume ðfat volume þ bone volumeþ: The total limb volume was estimated as volume of a cylinder, based on its length (L), corresponding to distance from acromion to minimum wrist circumference, and mean of 5 limb circumferences (axilla, maximum relaxed biceps, minimum above elbow, maximum over relaxed forearm, and minimum above styloid process) according to following formula: Total limb volume ¼ +C 2 L=62:8; where +C 2 is sum of squares of 5 circumferences of corresponding limb. Skin folds were assessed using a standard Harpenden caliper (Baty International, Burgess Hill, Sussex, United Kingdom). The fat volume was calculated as follows: +C =5 +S=2n L; where +S is sum of 3 skin folds for upper limb (biceps, triceps, and midforearm), and n represents number of skin folds measured on each limb. Bone volume was calculated as follows: p ðf DÞ 2 L; where D is humeral intercondylar diameter, F is a geometric factor (0.21 for upper limb), and L is limb length as measured above. Standard equations were used to predict percentage of body fat from biceps, triceps, subcapsular, and suprailiac skin-fold readings (37): %Body fat ¼ a log +4 folds b; where +S is sum of 4 skin-fold readings (in mm), and a and b are constants dependent on sex and age. 0.2 m above subject s chest and was supported by bottom stops of device. The player performed a successive eccentric concentric contraction from starting position. The eccentric action took weight over and behind individual s head, with elbow fully extended. At end of backward movement, when upper limbs were approximately parallel to ground and elbows were again slightly flexed, subjects pushed barbell to bring it back to starting position, keeping ir abdominal muscles well contracted and body stable without bouncing or arching of back. All subjects were familiar with technique, as y had used it regularly in ir weekly strength training sessions. A pretest assessment of 1RM PO was made during final training session. Warm-up for definitive test comprised 5 repetitions at loads of 40 60% of pretest RM PO. Thereafter, 4 5 separate attempts were performed until subject was unable to extend arms fully. The load noted at last acceptable extension was accepted as 1RM PO. Two minutes of rest was allowed between trials. Day 2 One-Repetition Maximum Bench Press. A detailed description of maximal strength and muscle power testing procedures is found elsewhere (19). In brief, maximal strength of upper extremity was assessed using a maximum 1-repetition successive eccentric concentric bench press action 1RM BP. Bench press (elbow extension) was chosen because it involves some arm muscles that are specific to overhand throwing (8). The test was performed in a squatting apparatus; barbell was attached at both ends, and linear One-Repetition Maximum Pull-- Over. This exercise is much like dumbbell pull-over, but intensity is added to movement by using a barbell. The bar was positioned about Figure 1. Power velocity relationships for heavy and moderate resistance groups (n = 18) before (dotted line) and after (solid line) 10 weeks of resistance training. The relationship is displaced slightly upwards after strength training. 2412

6 Figure 2. Comparisons of absolute and relative peak power output and muscle volume of upper limbs between heavy resistance (HR), moderate resistance (MR), and control (C) groups before and after 10 weeks of resistance training. *One-way analysis of variance (ANOVA) differs significantly (p, 0.05) between HR and C. + One-way ANOVA differs significantly (p,0.05) between MR and C. bearings on 2 vertical bars allowed only vertical movements. The bar was positioned 10 mm above subject s chest and supported by bottom stops of measuring device. The subject was instructed to perform a purely concentric action from starting position, maintaining shoulders in a 90 abducted position to ensure consistent positioning of shoulder and elbow joints throughout test (19,28). No bouncing or arching of back was allowed. Warm-up comprised 5 repetitions at 40 60% of perceived maximum. Thereafter, 4 5 separate attempts with 2-minute rest intervals were performed until subject was unable to Figure 3. Comparison of upper limb strength between heavy resistance (HR), moderate resistance (MR), and control (C) groups before and after 10 weeks of resistance training. ***One-way analysis of variance (ANOVA) differs significantly (p, 0.001) between HR and C. # One-way ANOVA differs significantly (p, 0.05) between HR and MR. ## One-way ANOVA differs significantly (p, 0.01) between HR and MR. extend arms fully. The last acceptable extension was accepted as 1RM BP. Handball Throwing Test. Explosive strength production during a handball overarm throw was evaluated on an indoor handball court. One type of throw (without run-up, T W ) was performed with 1 hand from a standing position, using an adapted chair. The trunk of player was immobilized by a blocked belt; shoulder was maintained in 90 of abduction and external rotation, and elbow was flexed to 90. For second type of throw (with run-up, T R ), subjects were instructed to use ir preferred technique to throw a handball as fast as possible through a standard goal. Both throw tests were undertaken after a 15-minute standardized warm-up and using a standard handball (mass 480 g, circumference 0.58 m). To simulate a typical handball action, players were allowed to put resin on ir hands, and y were told to throw with maximal velocity toward upper right corner of goal. The coaches supervised both tests closely to ensure that required techniques were followed. Each subject continued until 3 correct throws had been recorded, up to a maximum of 3 sets of 3 consecutive throws. A 1- to 2-minute rest was allowed between sets of throws and seconds between 2 throws of same set. Throwing time was recorded with an accuracy of second, using a digital video camera (SONY, HVR A1U DV Camcorder, Japan). The camera was positioned on a tripod 3 m above and parallel to edge of adapted chair. Data processing software (Regavi & Regressi, Micrelec, Coulommiers, France) converted measures of handball displacement to velocities. The reliability of data processing software was verified previously (4). The throw with greatest average velocity was selected for furr analysis. Training. Both HR and MR programs continued for 10 weeks. VOLUME 24 NUMBER 9 SEPTEMBER

7 Pull-Over and Bench Press Training and Arm Performance Figure 4. Comparisons of handball throwing velocity with (T R ) or without (T W ) upper limb run-up between heavy resistance (HR), moderate resistance (MR), and control (C) groups before and after 10 weeks of resistance training. *One-way analysis of variance (ANOVA) differs significantly (p, 0.05) between HR and C. **One-way ANOVA differs significantly (p, 0.01) between HR and C. ++One-way ANOVA differs significantly (p, 0.01) between MR and C. Two training sessions per week were performed on Tuesdays and Thursdays, immediately before normal handball training sessions. A researcher supervised each workout to ensure that proper procedures were followed. Both 1RM BP and 1RM PO exercises were used to determine appropriate loads for training sessions. 1RM values were reassessed at fourth week, and loads were updated for both HR and MR groups as necessary. Heavy resistance group: Each session included 2 exercises for upper extensor muscles (pull-over and bench press), with subjects training at 80 95% of ir personal 1RM. They performed 1 3 repetitions per set and 3 6 sets of each exercise with 3- to 4-minute rest between sets. Their program is detailed in Table 2. Both pull-over and bench press exercises require successive eccentric concentric loaded contractions performed at a slow velocity. The prescription of such loading intensities with such velocities is designed to produce greatest increases in maximal strength (22). Moderate resistance group: Each session included 2 exercises for upper extensor muscles (pull-over and bench press), TABLE 5. Comparison of force velocity test, upper limb muscle volume, and strength between heavy HR, MR, and C before and after 10-week trial.* HR MR C Pre Post Pre Post Pre Post Force velocity test Power (W) k Power (Wkg 21 ) k Power (WL 21 ) Maximal pedaling velocity (rpm) Maximal force (N) Force-velocity test 1RM (kg) Arm muscle volume { # RM (kg) Pull-over ** Bench press # *HR = heavy resistance group; MR = moderate resistance; C = control group; 1RM = 1 repetition maximum. Values are given as mean 6 SD. Two-way analysis of variance with repeated measure (group 3 time) was used to assess training related effects. MR is significantly different from C at p, k HR is significantly different from C at p, {HR is significantly different from MR at p, #MR is significantly different from C at p, **HR is significantly different from MR at p, MR is significantly different from C at p, HR is significantly different from C at p, HR is significantly different from MR at p,

8 with subjects training at 55 75% of ir personal 1RM. They performed 3 6 repetitions per set and 2 4 sets of each exercise with 1-to 1.30-minute rest between sets. Their program is detailed in Table 3. Both pull-over and bench press require successive eccentric concentric loaded contractions, performed as rapidly as possible. Statistical Analyses Standard statistical methods were used to calculate means and SDs. Training-related effects were assessed by a 2-way analysis of variance (ANOVA) with repeated measure (group 3 time). When a significant F value was observed, Sheffé s post hoc procedures were performed to locate pairwise differences. Percentage changes were calculated as ([posttraining value 2 pretraining value]/pretraining value) One-way ANOVAs tested any intergroup differences in percentage change. The reliability of T R, T W,1RM BP, and 1RM PO measurements was assessed using intraclass correlation coefficients (ICCs). The p # 0.05 criterion was used for establishing statistical differences throughout (we accepted p # 0.05, wher positive or negative differences, that is, a 2-tailed test). RESULTS The ICCs for measurements of strength and throwing velocity were all quite high: 1RM BP = 0.99, 1RM PO = 0.98, T W = 0.98, T R = The muscle power of both training groups increased relative to control regimen (Table 4). The typical parabolic relationship of power to velocity was seen in both training groups before and after training (Figure 1), with increases after training. Both programs enhanced absolute muscle power, although this advantaged disappeared if power was expressed per unit of limb volume (Figure 2). Training increased 1RM PO and 1RM BP (Table 4, Figure 3), with HR gaining substantially relative to controls over course of trial (p, for both comparisons). Moreover, HR induced larger strength increments than ML, because ir 1RM PO and 1RM BP values were statistically different (p, 0.05 and p, 0.01, respectively). Both programs also enhanced 2 indices of throwing performance (T W and T R ) (Table 5, Figure 4), although gain was significantly greater for HR than for MR (Figure 4). DISCUSSION Our findings substantiate our hyposis that short-term inseason resistance training enhances PP output, throwing velocity, and upper limb strength of experienced trained male handball players, wher a heavy or a moderate loading is used (Figure 4). A few previous studies have examined effects of concentric exercise on muscle power, throwing, and strength of handball players (10,12,24), but to authors knowledge, this is first study to compare players gains of PP, throwing velocity, and strength adaptations at moderate and heavy loads, using successive eccentric concentric exercises such as pull-over and bench press. This group participated in a 10-week supervised in-season strength training program, with a frequency of 2 sessions per week. Each session included 2 exercises for upper limbs (Pull-over and Bench press). Loads were 80 95% of personal 1RM, based on a succession of eccentric concentric muscle contractions at a slow velocity, and rest intervals of 3 4 minutes between sets. Relative to controls, HR showed improvements in both absolute muscle power (W) (11.3%; p, 0.01) and relative power (Wkg 21 ) (11.6%; p, 0.01) for upper limbs, but no changes when power was expressed per liter of upper limb muscle volume (WL 21 ) (Figure 2). This might suggest that gain in muscle power was largely attributable to an increase in regional muscle volume. However, this would be a little surprising, because resistance training with a heavy load does not usually induce a significant increase in muscle volume. In fact, average percentage increase of muscle power per unit of muscle volume (WL 21 ) for HR ( %) tended to be higher than for MR or C ( and %, respectively), although with small size of our groups and higher SD of relative measurements, intergroup differences were not statistically significant (Figure 2). Moreover, increases in upper limb muscle volume over course of trial did not differ substantially or significantly between HR and C ( vs %) (Figure 2, Table 4). This leads us to suggest that HR training did not increase muscle bulk appreciably and that increase in muscle power induced by HR program reflects neuronal adaptation, a well-accepted response to HR training (31). Schmidtbleicher (31) defined power as greatest impulse neuromuscular system could produce in a given time. Heavy loads are fundamental to power development, because high forces are associated with maximal motor unit recruitment according to Ôsize principle,õ with units also firing at higher frequencies (2,26). High force development may also inhibit force-feedback reflexes from Golgi tendon organs or improve synchronization of motor unit firing (16,21,30). In terms of muscle growth, development of large forces is also important to remodeling of muscle tissue (protein synsis and degradation) (9,23). The development of large forces stimulates receptor and membrane sensitivities, and muscle growth factors, reby triggering an increase in protein turnover and accretion of muscle protein (5). Heavy loading, particularly when muscle is actively stretched, may furr mediate muscle tissue growth by inducing greater reversible tissue damage (such damage seems a stimulus to muscle hypertrophy). Given importance of large forces to adaptative process, heavy training loads would appear to offer optimal stimulus to development of muscle power. Although prescription of a load based upon maximizing of mechanical power output appears to be an attractive strategy to enhance power of limbs, VOLUME 24 NUMBER 9 SEPTEMBER

9 Pull-Over and Bench Press Training and Arm Performance performance may be critically dependent on ability to exert force at speeds specific to a given athletic discipline. Although a powerful action is often associated with rapid velocities (e.g., in sprinting, jumping, and throwing), or activities such as lifting also have an important power component (5). In our study, longer contraction durations were associated with heavier loads; prescription of such loads would seem best suited to maximizing strength (22). Many authors have replicated finding of Gorostiaga et al. (12) that resistance training improves strength of leg extensors (12.2%; p, 0.01) and upper extremity muscles (23%; p, 0.01), whereas no changes are seen in a nonresistance activity (team handball practice) or a control group. However, in our study, gains of maximal strength for upper limbs were larger (HR: 57 and 16% for pull-over and bench press, respectively; MR: 28 and 6% for pull-over and bench press, respectively; C: 4 and 1% for pull-over and bench press, respectively) (Figure 3) than observed by Gorostiaga et al. (12). This could reflect differences in eir initial status of players or training programs and training exercises. Gorostiaga et al. (10) studied effect of an entire season of play (45 weeks) on power load relationships for arm extensor muscles of elite male handball players. They examined performance on 4 occasions: beginning (T1) of first preparatory period, at beginning (T2) and end (T3) of first competitive period, and at end of second competitive period (T4). Training was periodized from a high-volume, low-intensity phase during preparatory period to a low-volume, high-intensity phase toward competitive period. Values of 1RM BP obtained at T3 increased significantly (p, 0.01) compared with T1 (10). This result agrees well with our findings, because we noted a significant enhancement (p, 0.001) in both 1RM PO and 1RM BP for HR relative to C (Figure 3). The closer increase of 1RM upper limb strength in our study could be explained by greater number of weekly training sessions of Gorostiaga et al. (10). Moreover, it is more difficult to increase strength of trained athletes than younger and inexperienced subjects (31). Recently Marqueset al. (24) examined effect of 12 weeks of resistance training (2 3 sessions per week) in high-level handball; ir loadings were in range 70 85% of concentric 1RM BP. They noted a 28% increase of 1RM BP, However our HR group improved ir 1RM BP by only 16% (Table 4, Figure 3), probably because of participation in fewer weekly sessions for a shorter period. It is well known that MR training (around 70% 1RM) increases regional muscle volume (22). Our MR results are in agreement, showing significant increments of upper limb muscle volume relative to C and HR (Table 4, Figure 2). The loads were 55 75% of 1RM for both pull-over and bench press exercises; subjects executed 3 6 repetitions per set of each successive eccentric concentric exercise as rapidly as possible, with a rest interval of only minutes between sets (Table 3). Ten weeks of moderate strength training yielded considerable gains in upper limb muscle volume, which could explain significant enhancement of PP output relative to C (p, 0.05, Figure 2). This view is supported by disappearance of difference when PP output is expressed relative to body mass and especially to upper limb muscle volume (Table 4, Figure 2). Our observations furr show that wher expressed in absolute units or relative to body mass or muscle volume, power increases in MR group did not differ significantly from HR. Although percentage gain for MR was significantly greater than for C, it remained smaller than that for HR (Figure 2). This finding suggests that although short periods of MR training yield some gains of upper limb muscle power output, response is less than could have been obtained with high resistance training. As with power gain, upper limb muscle strength (wher assessed by 1RM pull-over or bench press) increased after moderate strength training, with gains of 24 and 6% for 1RM PO and 1RM BP, respectively (Figure 3). However, such gains did not statistically surpass gains seen in those following control regimen, and y were significantly less than those seen with HR training (p, 0.05 and p, 0.01, respectively). These results lead us to think that any trend to an increase of strength with MR training is insufficient to demonstrate a statistically significant and practically important difference. When training upper limbs, heavy loads are important to enhancing strength. The 10-week period of HR training led to a considerable gain in throwing velocities. The mean velocity of T R increased from to ms 21 (Table 5), a 42% gain (p, 0.01). In contrast, controls improved ir throwing velocity by only 9% (Figure 4). Similarly, T W showed a statistically significant of 34% in HR (p, 0.05), whereas change in controls was only 9%. It is difficult to compare results of few studies that have measured throwing velocities in male handball players because y differ markedly in a number of design factors, including method of measurement (photoelectric cells, radar, cinematography) (8,12,25,35), handball weight, players ages and skill levels (amateur or professional), and throwing techniques (standing, 3-step running throw, jump shot). Differences in intensity of training may also have contributed to conflicting results. Our data seem in accordance with findings of Gorostiaga et al. (12), who noted a significant enhancement (p, 0.001) of standing handball throwing velocity after 6 weeks of heavy upper limb resistance training. However, for se last authors, training exercises were supine bench press, half squat, knee flexion curl, leg press, and pecdec, (12) quite different exercises from those used in our study. Given training-induced adaptations observed in present study, we would conclude that both of programs that we evaluated boosted handball throwing velocity. However, heavy load training was superior, in that it enhanced both throwing modes (T R and T W ) (Figure 4). Certainly, a combination of strength, handball technique, and 2416

10 competitive skills training significantly enhanced maximal and specific-explosive strength of upper extremity over 10-week program. The increase in maximal upper limb strength should give players an advantage in sustaining forceful muscle contractions required during actions such as throwing, hitting, blocking, pushing, and holding (10). The increased velocity in both modes of throwing (T R and T W )is likely of major importance to successful play, because elite handball players achieve substantially higher velocities than lower level competitors (8 9% advantage in men [11] and 10 11% advantage in women [13]). Our study demonstrated a considerable (43%) increase of throwing velocity in response to eccentric concentric pull-over and bench press training exercises. A combination of high velocity and accurate throwing seem critical factors for success in handball (11,13). Although neurophysiological mechanisms contributing to increased throwing velocity are unknown, possible factors include more effective neural activation (17), a selective increase in cross-sectional area of fast-twitch fibers (17), changes in intrinsic muscular properties (7), an increase in myosin adenosine triphosphatase activity (14), better synchronization of motor units (27), and a higher firing frequency (15). Schmidtbleicher (31) attributed increase of muscle performance after heavy training to size principle of motor recruitment. In ir view, heavy training was needed to ensure recruitment of fast-twitch motor units; low loads did not overload muscle sufficiently to induce an adaptation. PRACTICAL APPLICATIONS The current study indicates that with only 2 sessions per week, 10 weeks of in-season bench press and pull-over resistance training with suitably adapted heavy loads elicits substantial enhancements in PP output, dynamic strength, and handball throwing velocity in male handball players. Moreover, this regimen is more effective than training at a lighter loading. It is quite practical to add this type of resistance training to traditional in-season technical and tactical handball training activities. We also recommend bench press and pull-over training for players who are regularly involved in or strength training programs to reduce risk of injury during a game. There are many potential neuromuscular explanations of observed changes in performance, and se merit furrinvestigation; when mechanisms are understood, it may be possible to realize even larger gains of performance. 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