Question:I have read that the stretch-shortening cycle is important to squatting, but what is it exactly and how is it trained?
Answer: The stretch-shortening cycle is defined as an eccentric-concentric coupling phenomenon in which the involved muscles are rapidly and forcibly lengthened, or stretch-loaded, and immediately shortened in a reactive or spring-like manner.
It consists of three phases: (1) the eccentric phase, or the negative portion of a lift, such as the descent in a squat, (2) a short pause between phases 1 and 2 called amortization, and (3) the concentric phase, in which the muscle produces the desired movement (the upward movement in the squat.)
In layman’s terms, your muscles and tendons can act like a rubber band in certain conditions. During the eccentric phase, elastic energy is increased and stored with a rapid stretch. A very short amortization phase leading to an immediate concentric phase will release this elastic energy, increasing the amount of force produced.
An important point to remember is that the stretch-shortening cycle is only activated in quick, explosive movements. You are losing valuable force potential with a slow descent and a pause at the bottom of the squat. As an example, perform a standing vertical leap and measure the height of the jump. Next, try an approach jump in which you take a few steps before you leap or a double jump in which you jump twice in rapid succession and measure the height of the second jump. Because of the eccentric stretch loading of the approach jump and the double jump, your vertical leap height will have increased from the static jump height.
There are two effective methods to improving your force generating capabilities. Plyometric training is used in many sports to increase starting strength and power. While not often utilized by powerlifters, we still may benefit from complex training, a system in which some plyometric training is incorporated with our training routine at periodized intervals.
A second method, which has become very popular in powerlifting, is the use of bands to increase the eccentric loading of a lift. Bands have actually been used to enhance speed, power, and strength in other sports such as swimming and sprinting. A recent study in the Journal of Strength and Conditioning Research using increased eccentric loading in the bench press shows promise that this method will increase maximal strength. While the methods used in this study may not be easy to duplicate in a normal gym setting and more research is needed to develop an optimal and user friendly training program, this study is also accompanied by anecdotal claims of the efficacy of band training, which cannot be discounted.
Question: I have been seeing reports of young children competing in powerlifting. Can’t heavy weight training stunt your growth?
Answer: The evidence clearly states that a safe and monitored strength training program is NOT harmful for even very young children. A moderate strength training program can help increase strength, decrease the risks of injury while playing sports, and increase bone density. The American Academy of Pediatrics has put forth a pro-strength training statement.
The American Academy of Pediatrics position on strength training supports the implementation of strength and resistance-training programs, even for prepubescent children, as long as well-trained adults monitor them and that they take into account the child’s maturation level. The only limitation the AAP suggests is to avoid repetitive maximal lifts (lifts that are one repetition maximum lifts or are within 2-3 repetitions of a one repetition maximum lift) until they have reached Tanner Stage 5 of developmental maturity. Tanner Stage 5 is the level in which secondary sex characteristics have been developed. Usually, in this stage adolescents will have also passed their period of maximal velocity of height growth.
The AAP’s concern that children wait until this stage to perform maximal lifts is that the epiphyses, commonly called growth plates, are still vulnerable to injury. It is repeated injuries to these growth plates that may hinder growth. For this same reason, two of the leading researchers in the field of youth fitness, Doctors Fleck and Kraemer, agree that repetitive maximal lifts should be avoided. However, Fleck and Kraemer and the AAP agree that a strength-training program that doesn’t include often-performed maximal lifting is beneficial for prepubescent and pubescent youth.
As long as the parents and coaches of young powerlifters do not sacrifice form and technique for lifts well beyond the capabilities of their young charges and limit the amount of maximal lifts they do, the inclusion of powerlifting in a well-rounded sports and recreational activity program will actually benefit their physical development.
Question: How much water weight can I safely lose before a competition?
Answer: Making weight is a common practice in many sports, and powerlifting is no exception. However, there are definite health risks associated with dehydration, as well as detriments to performance. Fluid loss of even 1% of body weight is associated with decreased thermoregulatory function, such as increased core body temperature. Further loss of up to 5% of body weight can result in potentially dangerous cardiovascular strain and inability to dissipate heat. If your federation requires you to weigh in the morning of the competition, you should plan on losing no more than 2% of your body weight within 48 hours of weigh-in to ensure a high level of performance. For a lifter who wishes to compete as a 181’er, this means that he or she should weigh no more than 185 pounds in the few days prior to the meet. Some research studies suggest that losing up to 4% of your body weight within 5 hours of competition is acceptable; however these results were accompanied by a high carbohydrate diet. In order to make weight, many powerlifters are forced to decrease their carbohydrate and overall caloric intake for up to two weeks before a meet. If your federation has 24-hour weigh in, a larger bodyweight reduction is possible, but you should still expect significant strength decreases, especially if you were following a low-calorie, low-carbohydrate protocol leading up to the competition.
If you cut weight before a competition, be sure to adequately hydrate yourself as soon as possible. A good powerlifting supplements sports drink with a glucose solution of about 6 to 8% will be absorbed most rapidly. Many lifters also consume a large amount of sodium after weigh-ins to avoid muscle cramping. However, it is not necessary to overdo this practice and in doing so many people neglect other electrolytes that are needed such as potassium and magnesium. Most sports drinks contain the proper the electrolyte ratio needed, and ingesting excess sodium is not required.