Speed-strength parameters such as muscular

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1 Journal of Strength and Conditioning Research, 2007, 21(1), National Strength & Conditioning Association POWER PRODUCTION AMONG DIFFERENT SPORTS WITH SIMILAR MAXIMUM STRENGTH ALPER AŞÇI AND CANER AÇIKADA School of Sport Science and Technology, Human Performance Laboratory, Hacettepe University, Beytepe, Ankara, Turkey. ABSTRACT. Aşçi, A., and C. Açikada. Power production among different sports with similar maximum strength. J. Strength Cond. Res. 21(1): The purpose of this study was to compare 1 repetition maximum (1RM) strength, maximum power (MP), linear momentum (Mp), and the loads of 1RM responsible for maximum power (MP%) and for linear momentum (Mp%) generated in explosive concentric bench press (CBP) motion among athletes from different sports. A total of 56 athletes (13 sprinters, 16 basketball players, 16 handball players, 5 volleyball players, and 6 bodybuilders) performed CBP in the loads of 40, 50, 60, 70, and 80% of 1RM with 1-minute rest intervals. MP and Mp were assessed during CBP by customized apparatus with 3 separate displacement transducers. There were no significant differences in MP, Mp, MP%, and Mp% among the athletes. The only significant positive correlation was found between overall 1RM and Mp for athletes (r 0.37). In conclusion, long-term sport-specific training adaptations do not play a major role on speed-strength parameters in athletes with similar strength from different sports backgrounds. KEY WORDS. bench press motion, power output, linear momentum, one repetition maximum INTRODUCTION Speed-strength parameters such as muscular power and linear momentum are important parameters for successful performance in explosively dominated sports. Linear momentum of a particular particle is the product of its mass and velocity, whereas muscular power is defined as the rate of doing work or, in applied terms, it is the explosiveness produced by the muscles during athletic events (12, 23). Although power output is calculated by using second derivation of displacement data, linear momentum requires only the first derivative in the inverse dynamic calculation. Maximum power generally occurs at approximately 30 80% of 1 repetition maximum (1RM) strength for lower- and upper-body movements (2, 9, 14, 15, 17, 18, 21, 23), and it is highly and positively correlated with 1RM (3, 4, 6, 19, 24). The high and positive correlations between 1RM and maximum power (r ) have been previously reported in rugby players (3, 4, 6), athletes with 7 weeks to 15 years of training history (24), and trained physical education students (19). Although maximum strength is a determining factor on maximum power, the correlation between 1RM and maximum power is altered with respect to athletes maximum strength. For example, Baker (3) reported that the relationship between 1RM and maximum power is low in stronger players compared with the weakest players. Besides 1RM, a sport-specific training background based on the nature of the sport might be another confounding factor on this relationship. Even though the correlation between 1RM and maximum power has frequently been studied in athletes from different sports without specifically considering their sports backgrounds, there have been no attempts to study this relationship in players with different sports training backgrounds and to evaluate how the sports training background influences this correlation when considering the athletes maximum strength level. A few studies, such as that of Izquierdo et al. (14), have reported significant differences in maximum strength and power outputs obtained in the bench press motion at the loads of 1RM among different sporting events (e.g., weightlifting, handball, road cycling, and middle-distance running). These differences in maximum strength and power outputs among different sporting events were explained by the interaction of long-term, sport-specific training adaptations with maximum strength (14). The aims of the present study were first to examine the differences in maximum power among athletes from different sports training backgrounds with similar maximum strength levels and second, to determine the relationship between 1RM and maximum power in these subjects. The influence of different sports training backgrounds on the correlation of maximum power with maximum strength could thus be evaluated by considering the maximum strength for controlling its effect. Finally, it was intended to examine the differences in the infrequently studied speed-strength parameter of the linear momentum among athletes from different sports backgrounds and to investigate its correlation with maximum strength for these subjects. The differences among sporting events and the correlations between 1RM and both maximum power and linear momentum as speedstrength parameters were examined in concentric bench press (CBP) motion. METHODS Experimental Approach to The Problem Fifty-six male athletes (13 sprinters, 16 basketball players, 16 handball players, 5 volleyball players, and 6 bodybuilders) with at least 2 years of strength-training experience on free-weight CBP volunteered to participate in this study. The testing procedure was performed over 2 sessions, the first of which determined the maximum load in CBP that each subject could lift for 1RM following evaluation of their height, weight, and anthropometric measurements. In the second session, the subject performed 1 repetition explosive CBP with non-bar release against the loads of 40, 50, 60, 70, and 80% 1RM respectively with 1-minute rest intervals between loads. The three-dimensional isotonic strength measurement system (3d-ISMS; Tümer Ltd, Ankara, Turkey) was attached to the Olympic-style barbell at the beginning of the motion to measure the displacement three-dimensionally with 100 Hz for the concentric part of each load. The power output and linear momentum were calculated based on the displacement-time data of the barbell-mass system for all loads after the raw data for all attempts were filtered using a low-pass filter with a cut-off frequency of 8 Hz. Statistical 10

2 SPORT-SPECIFIC BACKGROUND EFFECT ON POWER PRODUCTION 11 TABLE 1. Age (years) Height (cm) Weight (kg) BPE (years) Somatotype Endo Meso Ekto 7-SS (mm) Physical characteristics of the subjects; mean ( SD).* SR BP HP VP BB 24.1 (6.1) (7.1) 72.5 (7.1) 6.9 (4.2) 1.7 (0.3) 4.0 (1.2) 2.7 (0.8) 53.4 (13.8) 23.3 (3.5) (6.2) 84.3 (10.3) 4.6 (2.8) 2.2 (0.6) 4.0 (1.1) 2.4 (0.9) 88.9 (29.3) 22.6 (4.9) (6.2) 86.1 (8.9) 5.4 (3.4) 2.3 (0.5) 3.8 (1.1) 2.1 (1.1) 87.0 (25.7) 23.2 (3.8) (6.7) 81.6 (6.7) 7.0 (2.4) 2.1 (0.4) 3.9 (1.2) 2.6 (1.1) 78.4 (23.7) 24.2 (3.1) (7.0) 77.5 (7.2) 5.5 (2.6) 2.0 (0.2) 4.8 (0.5) 2.0 (0.5) 89.7 (28.2) *SR sprinters; BP basketball players; HP handball players; VP volleyball players; BB bodybuilders; BPE bench press experience; 7-SS sum of 7-site skinfold measurements. evaluation of differences was performed with Kruskal- Wallis technique among the different sporting events and with Pearson technique on the correlations between 1RM and both peak power and peak linear momentum. Subjects Fifty-six male athletes (13 sprinters [SR], 16 basketball players [BP], 16 handball players [HP], 5 volleyball players [VP], and 6 bodybuilders [BB]) who participated in regular strength training, which especially included bench press motion (in the present study it was termed bench press experience [BPE]), volunteered to participate in this study. The subjects were selected according to homogeneity of variances on 1RM among the sport groups. Written informed consent that outlined the testing procedures and possible risks of the study was obtained from all subjects. The mean SD of age, height, weight, BPE, somatotype, and sum of 7-site skinfold measurements ( 7-SS) of athletes from different sports backgrounds are shown in Table 1. Test Procedures The test procedure utilized in this study was performed over 2 sessions, the first of which determined the maximum load that each subject could lift for 1RM on CBP that was used for assessing the overall upper-body neuromuscular performance using the free-weight Olympicstyle barbell (25). In the second session, speed-strength variables of power and linear momentum were tested during explosive CBP with non-bar release against various loads of 1RM. A 5-minute recovery period was allowed between the 2 testing sessions. Maximum Strength Testing One repetition maximum strength was determined on CBP by using a free-weight Olympic-style barbell following a short warm-up period. In order to standardize the holding place for both hands on the barbell, a 90 elbow angle for both arms, which provided the same muscle participation in all trials, was determined by Guymon goniometer (Lafayette Instrument Co., Lafayette, IN). The subjects upper arms were parallel to the ground with a free-weight barbell when lying on the bench, before the warm-up period. In this position, the grasping places on the barbell of both index fingers were marked, and then all attempts were performed using these marked places during the testing periods (1). Thereafter, each subject performed a short warm-up consisting of 8 bench presses, which included both eccentric and concentric parts, of one-half body weight, using the barbell with the freeweights following 3 minutes of arm and shoulder mobilization exercises and upper-body muscle static stretches (9, 10). After the warm-up period, maximum strength was determined over 4 5 separate attempts, using progressively increasing loads. In order to prevent eccentric movement and bouncing action of the barbell on the chest, 2 spotters placed on each end of the barbell brought down the load on the subject s chest. With a command, the subjects performed only concentric motion. The last acceptable full extension of the arms with the highest possible load was determined as 1RM. A 1-minute rest period was allowed for recovery between attempts (9, 10). Speed-Strength Testing Speed strength was tested in the explosive type of CBP with non-bar release by linking the 3d-ISMS using relative loads of 40, 50, 60, 70, and 80% of 1RM respectively, following the 5-minute recovery period between the maximum strength test session and the speed-strength session. Subjects were instructed to perform 1 explosive concentric trial with each load, with a rest period of 1 minute, which allowed time to load and recover (10, 16). In order to familiarize themselves with the explosive CBP, subjects performed 1 repetition explosive CBP with a 21-kg standard free-weight (20-kg Olympic-style barbell plus 1- kg 3d-ISMS weight). The barbell displacement-time data of the relative loads of 1RM for each subject were recorded by linking the 3d-ISMS to the end part of the Olympicstyle barbell in CBP motion (Figure 1). Reliability Tests of Speed-Strength Variables Reliability of maximum strength (1RM) and speedstrength variables was assessed in 2 pilot studies. The first study was designed to establish the intraday intraclass correlation coefficient (ICC) of the variables in 2 trials separated by 1 day in 13 sport science student subjects (age years; height cm; weight kg; BPE years; 7-SS mm) who had at least 2 years of upper-body strength training background. Table 2 shows the mean and SDs of the trials, intraday ICC and coefficient of variations (CV) among the trials for 1RM, maximum power, and maximum linear momentum, with loads ranging from 30 to 90% of 1RM during bench press motion. The second study was then designed to assess the interday ICC of these variables in 2 trial morning and afternoon sessions, separated by at least 5 hours, in 21 sport science student subjects (age years; height cm; weight kg; BPE years; 7-SS mm) who had at least 2 years of upper-body strength training background. Table 3 shows the mean and SDs of the trials, interday ICC, and CV between the trials for 1RM, maximum power, and maximum linear momentum at 60% of 1RM during bench press motion.

3 12 AŞÇI AND AÇIKADA FIGURE 1. Connection of 3d-ISMS to the barbell during concentric bench press motion (CBP); A) initiation of CBP and B) completion of CBP. TABLE 2. Mean ( SD) scores, intraclass correlation coefficient (ICC), and coefficient of variation (CV) of interday measurements between the trials for 1 repetition maximum (1RM), maximum power (MP), and linear momentum (Mp) at loads of 30, 40, 50, 60, 70, 80, and 90% of 1RM. Day-1 Day-2 ICC CV (%) 1RM (kg) 79.6 (11.7) 80.7 (11.3) MP (W) % 1RM 30% 40% 50% 60% 70% 80% 90% 193 (73) 136 (43) 124 (32) 95 (32) 100 (30) 98 (67) 74 (32) 188 (65) 139 (33) 122 (27) 106 (37) 110 (46) 104 (50) 72 (31) Mp (kgm s ) % 1RM 30% 40% 50% 60% 70% 80% 90% 1.07 (0.29) 1.00 (0.14) 1.00 (0.26) (0.15) 0.81 (0.23) 6 (0.21) 0.78 (0.38) 1.03 (0.30) 0.98 (0.17) 0.95 (0.22) 0.85 (0.16) 0.79 (0.18) 0.79 (0.22) 0.80 (0.39) TABLE 3. Mean ( SD) scores, intraclass correlation coefficient (ICC), and coefficient of variation (CV) of intraday measurements between morning and afternoon sessions for maximum strength (1RM), maximum power (MP60), and linear momentum (Mp60) at 60% of 1RM. Morning Afternoon ICC CV (%) 1RM (kg) MP60 (W) Mp60 (kgm s ) 80.1 (12.5) 204 (50) 1.08 (0.36) 78.2 (12.4) 205 (53) 1.05 (0.41) cylindrical roller bearing and measured three dimensional displacement data of whole motion relative to the ground within an accuracy of 0.01 cm (Figure 2). Customized software was used to record the displacement-time data sampled at 100 Hz. Calibration of 3d-ISMS was checked before all testing sessions while it was attached to the Olympic-style barbell positioned statically on the bench. The mean displacement data for all 3 dimensions were found under cm in the static position. Data Analyses Before the power and linear momentum were calculated, the barbell displacement for each trial was first filtered using a low-pass filter with a cut-off frequency of 8 Hz and then differentiated by finite difference algorithm in MatLab software (MathWorks Inc., Natick, MA). The following kinematics data were then calculated for all loads of 1RM during the concentric part of bench press motion. The filtered displacement data (horizontal [d x ], vertical [d y ], and depth [d z ]) were differentiated to determine the horizontal, vertical, depth, and resultant velocity in m s (respectively, V x [Equation 1], V y [Equation 2], V z [Equation 3], V n [Equation 4]) and acceleration data in m s 2 (respectively, a x [Equation 5], a y [Equation 6], and a z [Equation 7]). V d t x x (1) V d t y y (2) V d t z z (3) Equipment The displacement-time data needed to calculate the power and linear momentum were measured by customized 3d-ISMS for all trials in CBP motion. The 3d-ISMS device included a signal processor, 12-bit analog-to-digital/digital-to-analog card, and 3 displacement transducers (Gefran Spa, Italy), one of which was a rectilinear displacement transducer, and the others were ballpoint rectilinear displacement transducers. A 3d-ISMS device was attached to the end part of the Olympic-style barbell by a V (V V V) ½ n x y z (4) a V t x x (5) a V t y y (6) a V t z z (7)

4 SPORT-SPECIFIC BACKGROUND EFFECT ON POWER PRODUCTION 13 Forces in 3 dimensions (F x [Equation 8], F y [Equation 9], F z [Equation 10]) and resultant force (F n [Equation 11]) were calculated in Newton (N). Where, W is weight of the test load of 1RM in kg and g is gravitational force in m s 2. Fx W g ax (8) F W g y ay W (9) Fz W g az (10) F (F F F) ½ n x y z (11) Instantaneous power (P n ) was calculated by Equation 12; instantaneous peak P n that occurred in any test loads of 1RM was termed the maximum power (MP) in watts (W). MP occurring in the percent of 1RM was recorded as MP%. Pn F V n n (12) Instantaneous linear momentum (p n ) was calculated by Equation 13; instantaneous peak p n that occurred in any test loads of 1RM was termed maximum linear momentum (Mp) in kgm s. The Mp occurring in the percent of 1RM was recorded as Mp% (where in Equation 13, W is weight of the test load of 1RM in kg, g is gravitational force in m s 2, and V is the change in velocity in m s ). p W g n V (13) Statistical Analyses Statistical analyses were carried out on SPSS for Windows (SPSS, Inc., Chicago, IL). Since the athletes were selected according to maximum strength level which provided similar homogeneity of variances among the sporting events in the 1RM test, the sample sizes of 2 groups in the study were less than 10. As suggested by Welkowitz et al. (26), if sample size is less than 10, a non-parametric test would be useful to determine the comparisons among the groups. Therefore, in the present study, by considering small sample sizes in 2 groups, a non-parametric test of Kruskal-Wallis statistical technique was conducted to determine the differences among the sporting events for warm-up weight, 1RM and the test loads of 1RM (40, 50, 60, 70, and 80% of 1RM). Furthermore, the Kruskal-Wallis technique was also separately carried out among the sporting events for MP, Mp, MP%, and Mp%. In order to determine the relationships between 1RM and both MP and Mp, the Pearson Product Moment Correlation technique was used. Statistical significance was determined using a probability level of p RESULTS Table 4 compares the mean and SDs (mean SD) of 1RM, MP, and Mp values among the sporting events. Furthermore, it also shows the comparison of the loads responsible for MP% and Mp% relative to 1RM among the different events. These results show that all events had statistically similar maximum strength levels. The MP occurring in 50 63% of 1RM ranged from 190 FIGURE 2. Mechanical structure of 3d-ISMS. to 300 W, whereas Mp occurring in 42 59% of 1RM ranged from 1.20 kgm s to 1.47 kgm s in the selected sporting events. No significant differences were found on MP, Mp, MP%, and Mp% among the events (p 0.05) (Figure 3). The correlation between 1RM and both MP and Mp is shown in Table 5. A statistically significant but low correlation was found between 1RM and Mp (r 0.37, p 0.05). DISCUSSION In the present study, MP and Mp were calculated as an indicator of muscular speed-strength performance, and one of the findings was that there were no significant differences in 1RM, MP, and Mp among the groups of athletes from different sports during explosive CBP motion with non-bar release. Another finding of this study was that there was no significant correlation between 1RM and MP for the pooled data. In addition, a significant but low correlation was found between 1RM and Mp. Finally, no significant differences were found on loads of 1RM responsible for the MP% and Mp% among the groups of athletes. This study revealed that although no significant dif-

5 14 AŞÇI AND AÇIKADA TABLE 4. Mean ( SD) scores of 1 repetition maximum (1RM), maximum power (MP), maximum linear momentum (Mp), and the loads responsible for maximized power (MP%) and linear momentum (Mp%) relative to 1RM among sporting events.* SR BP HP VP BB 1RM (kg) MP (W) Mp (kgm s ) MP% (% 1RM) Mp% (% 1RM) 82.3 (18.4) 227 (155) 1.47 (0.84) 52 (12) 59 (16) 79.2 (14.1) 232 (201) 1.45 (0.97) 50 (14) 57 (16) 77.2 (12.8) 190 (98) 1.30 (0.42) 58 (16) 51 (14) 75.5 (12.2) 300 (307) 1.37 (0.53) 54 (117) 54 (16) *SR sprinters; BP basketball players; HP handball players; VP volleyball players; BB bodybuilders (10.8) 221 (96) 1.20 (0.26) 63 (16) 42 (4) ferences were found among the sporting events, the highest MP was found for VP (300 W), while the lowest value was obtained for HP (190 W). Cronin et al. (9) reported that there was a significant difference on the maximum power output between the low (72.0 kg) and high (100.9 kg) maximum strength groups at 40% of 1RM, whereas significant differences were found between the groups on average power in the loads of 40, 60, and 80% of 1RM in CBP motion. Further supporting data by Baker (3) and Baker et al. (7) stated that there was a significant difference in maximum power between high and low level rugby players, and maximum power for different level rugby players ranged between 461 and 600 W in the loads of 40 80% of 1RM. Furthermore, Izquierdo et al. (14) found that maximum average power outputs ranged between 200 and 391 W for weightlifters, handball players, cyclists, middle distance runners, and control subjects. They also found that there were significant differences in 1RM and power output among the sporting events in CBP motion. Baker (3) revealed that large differences in 1RM between the groups result in differences in maximum power with an increased load. Based on this finding, it could be stated that the differences in power output among sporting events in the study by Izquierdo et al. (14) could be due to the different maximum strength levels. In the present study, even if the nature of the sports were different, and maximum strength of the athletes from these different sports were similar, the similarity in power outputs of the athletes from different sports could be mainly due to the similar maximum strength level and athletic training backgrounds on neuromuscular adaptations. Thus, the long-term sport-specific training backgrounds, which affect muscular factors, including muscle cross-sectional area and muscle fiber type, in addition to the neural mechanisms such as motor-unit recruitment, rate-coding ability, and synchronization, might not have resulted in any maximum strength level difference. Although power output is calculated using second derivation of displacement data, linear momentum requires only the first derivative in the inverse dynamic calculation. Bartlett (8) stated that the noise within the displacement data of human movement may be 20 times higher in the second derivative compared with the first derivative. It can therefore be stated that the linear momentum, calculated by using only the first derivative, has an advantage on power output by reducing the effect of noise and producing the smoothed data. In the literature, Pampus et al. (22) used only the linear momentum of accelerated mass as an indicator of muscular performance during the lying barbell-rowing movement. In the present study, the highest Mp was found in SR (1.47 kgm s ), while the lowest value was obtained for BB (1.20 kgm s ). There were also no significant differences, as with MP, among the athletes from different sports in explosive CBP motion. However, there were no maximum linear momentum data for upper-body extremity exercises in order to compare this result with related studies. This result revealed that the similarity in the maximum linear momentum data of athletes from different sports could be mainly due to the same maximum strength level of the athletes, as with maximum power output, rather than the long-term training effect from different sports. Maximum power and linear momentum in the present study was different from all the above studies. This could be due to 4 different factors: different testing motion with bar released or non-bar released, the different data gathering systems, method of power calculation, and the filtering technique applied to the data (11). The dissimilarity among the results of the present study and those of previous studies could be the different test motion to evaluate the chest muscle performance with bar released or non-bar released. Newton et al. (20) revealed that in the non-bar released motion, deceleration occurred in the wide range of the movement and, therefore, power production was reduced compared with bar released motion (10). In the present study, speed-strength parameters were determined in CBP motion with non-bar release whereas Baker et al. (3, 4) used bar released motion. The second factor could partly be attributed to different instrumentation used in the experimental design. For example, the power output was determined by plyometric power system as in Baker s (3) study. On the other hand, Cronin et al. (9) used a linear transducer which measures vertical displacement with 1-mm sensitivity, while Mayhew et al. (17) used a digital timing system for measuring power output. In the present study, in contrast to the above studies, 3 separate linear transducers with 1-mm sensitivity that measured the displacement in 3 separate dimensions in bench press motion were used, and the power output was calculated over resultant displacement. The third factor is that the calculation method used in the power and linear momentum was somewhat different in this study. The fourth factor, the use of different filtering techniques on the displacement data, may be another reason for differing results. It was considered that for each data set, as in this study, there was a need to use a filtering technique to eliminate the noise resulting from systematic and random errors (13). In many studies, there was very high correlation between maximum strength and muscular power. Moss et al. (19) found a strong correlation between 1RM and maximum peak power output (r 0.93) in elbow flexion exercise, while Bemben and McCalip (8) found moderate correlations between 1RM and both peak power (r 0.76) and average power outputs (r 0.80). More recently, Stone et al. (24) found strong correlations between 1RM and both countermovement jump and static squat jump power outputs up to 90% of 1RM (r ). Further supporting data by Baker (3) reported that 1RM and maximum power output were highly correlated in high and low level rugby players. However, this correlation was altered in athletes with different maximum strength levels. The relationship between 1RM and power output in lighter loads (40% of 1RM) is lower than that of higher loads

6 SPORT-SPECIFIC BACKGROUND EFFECT ON POWER PRODUCTION 15 FIGURE 3. The graphical presentation of maximum power and linear momentum scores and relative load of 1 repetition maximum (1RM) strength according to sporting event; a) maximum power (MP); b) maximized power relative to 1RM (MP%); c) maximum linear momentum (Mp); d) linear momentum relative to 1RM (Mp%); SR sprinters; BP basketball players; HP handball players; VP volleyball players; BB bodybuilders. TABLE 5. The correlation coefficients (r) between 1 repetition maximum (1RM) and both maximum power (MP) and maximum linear momentum (Mp). 1RM r MP (W) Mp (kgm s ) * * Denotes significant correlations between the variables, P (80% of 1RM). In addition, this correlation for the stronger athletes was lower (r ) than that of the weakest athletes (r 0.85) (3, 7). Thus, maximum strength appears to play a major role on the power product rather than speed with an increased load, and increases in force result in an increase in power output (3, 7, 24). On the other hand, a significant but low-level positive correlation was found between maximum strength and linear momentum in the present study (r 0.37; p 0.05). Only one related study, that of Pampus et al. (22), obtained a higher correlation between maximum isometric force and the load of 1RM resulting in maximized linear momentum (r 0.92). Therefore, it could be stated that the maximum linear momentum may be more sensitive to sport-specific neuromuscular adaptations than power output in athletes from different sports with similar maximum strength levels. In the literature, loads of 30 50% of 1RM (9, 14, 15, 17, 18, 20), 40 60% of 1RM (23), 46 62% of 1RM (2) and 65% of 1RM (5) are suggested to be the loads that best optimize power output. Maximum and average power outputs in many studies were maximized at the load range of 30 50% of 1RM for bench press motion (9, 14, 17, 21). In the present study, MP was obtained at a range between 50.0 and 63.3% of 1RM, whereas Mp% was obtained at a range between 41.7 and 58.5% load of 1RM in explosive CBP motion. However, the variation between the lower and upper values of sporting events, 13.3% for MP% and 16.8% for Mp%, was too large, thus no significant differences were found on the relative loads of maximum power and linear momentum among athletes from different sports. Baker (3) stated that in the periodization plan of the athletes, power and speed-strength qualities may be focused after an adequate maximum strength has been attained. This suggests that power production percent load of 1RM may be altered by the level of maximum

7 16 AŞÇI AND AÇIKADA strength. Based on Baker s study (3), the reason for the higher loads of 1RM compared with the literature on power production, it could be stated that the subjects in this study have not participated in a specialized training for the chest muscles in this movement, and this may be due to the nature of sports not requiring any such training. This result also revealed that neuromuscular adaptations depending on long-term sport-specific training do not create any differences in relative resistances of maximum power and linear momentum in athletes with similar strength levels from different sports backgrounds. In conclusion, maximum power and linear momentum and the percentage loads of 1RM responsible for the largest scores did not differ among athletes from different sports. In the pooled data, only maximum linear momentum was correlated with maximum strength. These results indicate that long-term sport-specific training adaptations do not play a major role on power and linear momentum productions as speed-strength parameters in athletes with similar strength levels from different sports backgrounds. Furthermore, it can also be stated that the maximum linear momentum might be more sensitive to determination of sport-specific neuromuscular adaptations than power output in athletes from different sports with similar maximum strength levels. PRACTICAL APPLICATIONS In the present study, the differences in maximum power and linear momentum were not significant among athletes from different sports backgrounds. In addition, the pooled data of this study showed that maximum strength was not significantly correlated with power output, whereas a significant relationship was found between maximum strength and linear momentum in athletes with similar maximum strength levels from different sports backgrounds. The moderate to high correlation between maximum strength and muscular power was reported in the literature. The similar maximum strength scores of athletes in the present study may be one of the reasons that the high correlation between 1RM and power as reported in the previous research was not found. This result may be explained by the long-term sport-specific background with similar content of regular weight training. Thus, long-term sport-specific background with regular weight training did not have any significant difference on upper-body speed-strength performance in athletes such as sprinters, handball players, basketball players, volleyball players, and amateur bodybuilders with similar maximum strength level. The results of the present study also indicated that no differences in maximum strength as a result of long-term sport-specific background with regular weight training could result in similar power productions among different sports. It can be concluded that the improvement of upper-body power depends on maximum strength training rather than sportspecific training. In other words, maximum strength plays a major role on maximum power and linear momentum rather than long-term sport-specific background in athletes from different sports. In order to improve the speed-strength performance, a group of athletes should be trained with the maximum strength methods in weight-training sessions. On the other hand, velocity-specific adaptations should be obtained by speed-strength type training. In the assessment of velocity-specific adaptations, from either speed-strength type training or sport-specific training, maximum linear momentum may be a more sensitive variable than maximum power after sport-specific and speed-strength type training. REFERENCES 1. ABENDROTH-SMITH, J., AND S. GRISWOLD. The effects of grip with on bench press performance using novice lifters. North American Congress on Biomechanics. 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