The purpose of this study was to examine the effects of a lower-limb resistance strengthening and plyometric protocol while wearing the resistance apparatus on one repetition maximum in the parallel back squat and 20-yard short shuttle agility test focusing on power alone.
As a result of the study, it can be determined that future studies must be longer and have more participants. Results in the study concur that differences between groups over a 10 week period were not significant. As a result of having a low number of participants, significance was not achieved. When training for power it is important to stay consistent on the continuum of repetition ranges associated with various training goals. Baechle and Earle (2000), suggest that repetitions for power be in the range of 1 to 5. Although this was achieved by weeks 7 and 8 for load ranges of 75 to 90% of 1 repetition maximum, the first 6 weeks according to Baechle and Earle (2000) had repetition and load ranges more consistent with hypertrophy and muscular endurance. Power is usually measured by speed with low reps and lower estimated load ranges. Future studies should work on staying in this power repetition range when working with experienced participants. As seen in the studies by Dugan (2004) and Zink et al. (2006), load is an important factor when prescribing power. Zink et al. (2006) points out that ranges from 40-50% were associated peak power with experienced lifters. All of the participants were physically active prior to the initiation of the study and were familiar with plyometric and resistance training because of previously participating in organized sports. This suggests that the current protocol may not have been a strong enough stimulus to elicit changes in the trained participants. Future research should include untrained and informed individuals to determine if greater improvements in the performance measures would be observed with this protocol. Hypothetically speaking, highly trained participants would exhibit less improvement than untrained subjects with this type of training.
Program design is the idea that training principles be adhered to during a program period. The three training principles that should be incorporated in all training programs are specificity, overload and progression. A lack of attention to any one of these principles often produces less than desirable training outcomes (Baechle and Earle, 2000). Specificity is doing the exact skill that is set out to be improved upon. It states that you are doing the exact skill or not at all. Overload refers to stressing a muscle or energy system with a workload that is beyond its present capacity. Effort must be great enough to exceed this threshold for muscular or metabolic fatigue to trigger an adaptive response. Gradually increasing the intensity of a training program is referred to as progression. Future studies should incorporate all three training concepts with much more detail when designing a training program to optimize power and agility.
Immediately, this is where some of the flaws come into the scope of the program. Specificity was not utilized for agility training. The only time the open skill was practiced was during pre and post testing. Although muscle groups were trained with the resistance and plyometric program, the skill itself was not specifically trained. So in future studies, practice skills that will be tested as-well-as incorporate lateral movements into the training protocol. Movements in all three planes of movement must be practiced to achieve a maximal functional capacity. Also, since the squat is a total-body power exercise, a total-body training protocol must be used in future studies. The quote, “Your only as strong as your weakest link” is true in this case. If you do not have maximum flexibility in joints, core strength and overall body strength, the back squat will be a tough exercise to measure total-body strength if the body is not trained in other ways.
Progression was seen in this design as decreased rest intervals and increased intensity were used. Despite this, there was a lack of increasing the volume (sets and reps), increasing the number of exercises and exercise selection. The same exercises were consistently used, the same amount of exercise reps and ranges were used and there was really no increase in volume throughout. A recent article suggests an increase in volume may not be necessary for future studies as increasing the time under tension may be an optimal way to increase strength and power. Stoppani (2006) suggests that increasing time under tension for reps of 1 to 6 will from anywhere from 1 to 20 seconds will increase power and strength.
Using the overload principle is equally important as using specificity and the progression principle. In this study, the apparatus + exercise group performed sets at the tune of 10% less than their estimated one rep maximums then the exercise group due to the added resistance the apparatus provided with bands. Doing the study with both the exercise group and apparatus + exercise group doing the same percentage by weight could have shown significance difference between groups. When using a bungee cord for resistance during squat training, compared to no bungee cord use, the experimental group improved more than three hundred percent when compared to the control group in back squat, as displayed in the study by Anderson et al. (2008). Future studies need to have groups performing the exact same percentage of one rep maximum's to see if the variable truly works. You can see by the results that the exercise group improved by 1.78% more than the apparatus + exercise group when looking at percentage of estimated 1 RM weight lifted. Even though not significant, you draw the conclusion that the apparatus did not work. One of the things you can draw from this is that 10% reduction in the apparatus +exercise accounted for about the same increase in max squat output in percentage by weight. A future study could go as far as hypothesizing that wearing the apparatus will significantly (by about 10%) increase maximal squat output compared to a group using the same protocol without an apparatus.
With this estimate of 10%, it is important to note the focus of the study which is power. Power is the time it takes to move a weight across an error. The study of Wallace et al. (2006) points out that a band that provides 20% of the 1RM is best for increasing power and force compared to a band that provides 35% of the 1 RM when performing back squat in recreationally active adults. That being said, again with this only 10% estimate accounting for that missed weight in this study, maximum results were not achieved in this study if you employ what was found by Wallace et al. (2006). Maybe an increase in the amount of resistance with the apparatus would be sufficient. FlexNimbo produces bands that reportedly give resistance at the tune of 50 lbs. and 75 lbs. Studies need to be done on exactly how much force is exhibited throughout the body while wearing the apparatus. The elasticity of the bands is different for people with different heights and body types.
Taking into account these percentages that were lifted by each group, future studies must realize if a maximum effort is given because more often than not, maximum effort yields maximum results. Max effort allows for the overload principle to really take its place. For future studies, I am recommending the OMNI RPE Scale (Lagalley, 2006) be placed into the program design to gage effort on a daily basis. It is a scale, much like that of the Borg Scale which measures how the subject is feeling. Using this scale could help prescribe higher intensities on a day-to-day basis to give a max effort instead of just going through the motions. Of course this will be based on the goals of the workout, but the goal of the overall program is to stress the total body by training all the systems (phosphocreatine, anaerobic, and aerobic).
Flaws in the way the resistance band apparatus fit the participants was a setback of the study. Obviously, you can make adjustments to the apparatus, but there is no universal way to adjust the apparatus on an individual basis. This would believe one to think that the resistance level and distribution of the resistance was different on each individual. Furthermore, for example, the level of resistance throughout the range-of-motion on a back squat was not consistent. Standing straight up and taking the bar of the rack is near optimal resistance. Moving to the lowering phase of the exercise, the resistance decreases, and as you power up, the resistance becomes more exuberant throughout the body. This was very similar to using chains on a barbell. Future studies should incorporate some type of adjustment protocol to ensure proper fit and resistance for each participant, but more importantly maintain the integrity of the study by ensuring safety.
Taking into further accounts such as neuromuscular development, technique, and individual assessment is also essential. Using the criteria sheet set forth in Appedix G for the back squat assessment was crucial for development, however, the overall technique was average at best. Even though the athletes were recreationally active and had previous experience in resistance training protocols, making the study longer is essential to building the structure base of the athlete neuromuscularly so we can see that overload principle take ahold. An eight-week study was not sufficient to see results because the subjects had not been coached correct technique on a daily basis and had not been motivated to improve their technique to see results.
This was the first study to incorporate the use of the resistance training apparatus that had both plyometric and strength training exercises in a workout. The data demonstrate that there were no significant differences between or within groups over time. There is no evidence that suggests using a resistance band apparatus is better than not using one to train on this population. Without change to this pilot study design, the apparatus will not be of any significant value to traditional weight training. If these effects are present in future studies, then adding resistance training apparatus to plyometric and strength training programs will not provide any additional benefits to power or agility performance over time.