Light-Weight Resistance Training For Strength and Power - Article Example

 Light-Weight Resistance Training For Strength and Power Abstract Two studies were reviewed to study the use of incremental weights in resistance training programs to increase strength and improve performance in terms of power produced in sports persons. While one focused on measurement of jumping power in terms of 1RM squat using incremental weights for subjects with varying strengths and experience in resistance training, the other studied the effect of light weight, high repetitive resistance training program on muscular strength (among other variables). Both the studies indicate that a resistance-training program with lighter weights may increase strength, while one also suggested the use of highly repetitive activities. An increase in strength levels can cause an upward shift of the maximum strength where jumping power peaks. 1. Introduction Sports performance is often measured in terms of power generated, which is affected by two factors, force and velocity (Stone et al. 140). However, increase in resistance during sports leads to increase in force production while reducing the velocity. Therefore, peak power (PP), which is the instantaneous measure of power generated in a particular movement at optimum force and velocity, is of importance (Stone et al. 140). While PP is likely to depend on the type of training or sport performance, studies suggest that the highest values for the same occur at 30% of peak isometric force and 30-50% of the 1 repetition maximum (1RM), approximately (Harris; Kaneko; Newton; and Perrine; cited in Stone et al. 140). Stone et al. acknowledge a popular belief that power production is related to maximum strength, which is the ability to produce force (Stone (1993), cited in Stone et al. 140). They cite several reasons for this – a stronger person may find it easier to accelerate a given weight; a greater percentage of type two fibers may contribute to a greater power output; and strength training increases the maximum strength, causing additional simultaneous alterations that may affect power production (Stone et al. 140). The increased popularity of resistance-training in physical conditioning programs can be attributed to their interest in increasing sport performance and improving body composition, according to O’Connor and Lamb (1). They cite several studies that have proved the positive effect of heavy, low-resistance training programs on muscular strength (W. Stone, cited in O’Connor and Lamb). Stone et al. suggest that there is no clear correlation between maximum strength and power production, as existing studies offer different conclusions. However, a better understanding of this correlation is likely to result in better designed resistance-training programs to improve power, and thus sports performance. The purpose of this literature review is to compare two studies in order to find a means to improve strength and power using resistance training. In the first study, Stone et al. examined the relationship between 1RM squat and PP production. They considered countermovement and static unweighted as well as weighted squat jumps (Stone et al. 140). The second study by O’Connor and Lamb studies the effect of light, high repetition resistance training called BodymaxTM on strength and skin-fold measurements in active women. 2. Methods 2.1 Approach Stone et al. used an experimental approach where the subjects performed squat jumps with or without counter movement. This took place in two sessions, 1 week apart. At the first session, countermovement squat jumps (dynamic condition) were performed with incremental weight raises, from 0 to 1RM, with focus on minimizing fatigue. During the second session, the squats where performed in the static condition, with similar incremental weight raises. On the other hand, O’Connor and Lamb used a parallel, randomized control trial to compare strength and skin-fold thickness between subjects who trained with the resistance training program and control subjects (4). While the control group participated in aerobic exercise for 60 minutes, the resistance training involved participation in a program called Bodymax™, which involves usage of light, variable weights and high repetitions (O’Connor and Lamb 4). Both the programs took place for three times a week for 12 weeks. 2.2 Subjects In the study conducted by Stone et al., 22 men in the age-groups of 17-30 years with squat training histories of 7 weeks to 15+ years participated. Based on the 1RM squat, they were divided into two groups one containing the 5 strongest and the other containing 5 weakest subjects (Stone et al. 142). On the other hand, participants in the study by O’Connor and Lamb were Caucasian women with a mean age of 38±5 years (4). While the participants had attended an aerobic program for 3 days a week for at least one year before the study, they had excluded resistance training from their routine for two months. Two random groups were assigned – 20 participants in a resistance-training group and 19 in a control group (O’Connor and Lamb 4). 2.3 Measurements Stone et al. determined visually and measured the squat jump depth for consistency. They used V-scope 120 (Lipman Electronic Engineering Ltd., Ramat Hahayal, Israel) to measure squat-jump power. This movement tracking device gave the displacement and the accompanying software calculated force and PP. In the study by O’Connor and Lamb, muscular strength was measured as in the study by Stone et al., using increasing increments of weights up to 1RM in six different events – seated leg curl, seated leg extension, lateral pull down, shoulder press, chest-press, as well as per dec (4). 2.4 Statistical Analysis Stone et al. calculated the relative intensity and normalized the data for maximum strength levels. They used the Pearson product moment method to calculate the correlations and Student’s t-tests to calculate the differences in group maximum strength and power. O’Connor and Lamb (6) calculated repeated measures analysis of variance (ANOVA) between the subject groups and within pre-test and post test factors. They used Turkey HSD post-hoc procedure to identify significant differences between means and estimated the magnitude of effects of the training using the Clarke-Carter method (Clarke-Carter in O’Connor and Lamb). 3. Results Stone et al. found a decrease in power production with increase in intensity or percentage of 1RM in both dynamic and static conditions, with the highest correlation at 50% 1RM. The static conditions showed higher correlations than the dynamic conditions. A comparison of maximum strength between the 5 strongest and 5 weakest subjects suggests greater values at 1RM for the strongest group. In terms of power output too, the strongest group showed higher values at all intensities (the peak being at 40% of 1RM) compared with the weakest group (Stone et al. 143). O’Connor and Lamb (6) found that the resistance-training group showed a significant improvement in total muscular strength compared with the control group (Figure 3). In terms of post-training strength (Figure 4), the resistance group showed higher values than the control group (O’Connor and Lamb 7). Figure 1 Table showing power output as a function of relative intensity Source: Stone et al. Figure 2 Table showing maximum power output for 5 strongest and 5 weakest subjects. Source: Stone et al. Figure 3 Strength measures in control and resistance groups, pre-test vs. post test. Source: O’Connor and Lamb. Figure 4 Interaction of Group x Test for Total Muscular Strength. Source : O’Connor and Lamb. 4. Discussion According to Stone et al, the strong correlation between the 1RM squat and power produced (Figure 1) suggests that an improvement in 1RM squat can cause an increase in jumping power. To support this claim, they point to their finding that the group with five strongest subjects showed better power outputs than the group with the five weakest (Figure 2). However, they emphasize that these correlations between 1RM and power are not linear and this could indicate that after a peak, maximum force was no longer exerted. They offer several plausible reasons for this - maintenance of weights may have caused a reduction in force, or further acceleration was difficult after expending too much energy at the peak. Keeping this in view, lighter weights can also be associated with maximum strengths, they suggest. The better results showed by the strongest group suggests that enhancement in maximum strength levels can cause PP production at higher maximum strength. To increase muscular strength, O’Connor and Lamb also recommends light weights in the resistance-training program, but along with high repetitions (8). While they did not have an untrained group to show possible improvements in muscular strength with a program such as Bodymax, the use of the control group is a legitimate alternative, they suggest. An advantage with such a group is that they are less likely to drop out of the program (Plouz-Snyder in O’Connor and Lamb). Although both groups underwent physical training, the resistance-training group showed significantly improved muscular strength for some activities such as leg curl, leg extension, lateral pull-down, and per dec. 5. Conclusions As more and more fitness programs for sports persons are incorporating resistance training in order to increase muscular strength and improve sport performance in terms of power produces, we reviewed two studies for the same. While one focused on measurement of jumping power in terms of 1RM squat using incremental weights for subjects with varying strengths and experience in resistance training, the other studied the effect of light weight, high repetitive resistance training program on muscular strength (among other variables). Both the studies indicate that a resistance training program with lighter weights may increase strength. An increase in strength levels can cause an upward shift of the maximum strength where jumping power peaks. This increase in strength levels can be achieved using a light weight, highly repetitive resistance training program. Therefore, it is imperative to design a resistance-training program with light weights for sports persons aiming to improve their performance. However, further research is required to assess which sporting activities benefit from this training and the type of resistance training they require. Works Cited American College of Sports Medicine. Guidelines for Exercise Testing and Exercise Prescriptions. 5th edition. Media PA: Williams and Wilkins, 1995. 55-58. Clarke-Carter, D. Doing quantitative psychological research. Hove, UK: Psychology Press, 1997. Harris, G.R., M.H. Stone, H.S. O’Bryant, C.M. Proulx, AND R.L. Johnson. Short term performance effects of high speed, high force or combined weight training. J. Strength Cond. Res. 14 (2000). Kaneko, M., T. Fuchimoto, H. Toji, AND K. Suei. Training effect of different loads on the force velocity relationship and mechanical power output in human muscle. Scand. J. Sports Sci. 5 (1983). Newton, R.U., W.J. Kraemer, K. Hakkinen, AND A.J.Murphy. Kinematics, kinetics and muscle activation during explosive upper body movements. J. Appl. Biomech. 12 (1996). O’Connor, Tracey E. and Kevin L.L. The effects of Bodymax high-repetition resistance training on measures of body composition and muscular strength in active adult women. J. Strength Cond. Res. (2003). Perrine, J.J. The biophysics of muscle power output: Methods and problems with measurement. In: Human Muscle Power. N.L. Jones, N. McCartney, and A.J. McComas, eds. Champaign, IL: Human Kinetics (1986). Ploutz-Snyder, L.L. AND E.L. Giamis. Orientation and familiarization to 1RM strength testing in old and young women. J. Strength and Con. Res. 15.4 (2001). Stone, M.H. Position/policy statement and literature review for the National Strength and Conditioning Association on ‘‘Explosive Exercise’’. NSCA J. 15.4 (1993). Stone, Michael, Harold O’Bryant, Lora McCoy, Robert Coglianese, Mark Lehmkuhl, and Brian Schilling. “Power and maximum strength relationships during performance of dynamic and static weighted jumps.” J. Strength Cond. Res. 17.1 (2003) 140–147. STONE, W. AND S.P. COULTER. Strength/Endurance effects from three resistance training protocols with women. J. Strength Con. Res. 8.4 (1994). Read More