Resistance Training and Adolescent Females

Resistance training has been the exercise regime of choice for many adults and has proven to be enjoyable and effective. However, in previous years, it has been controversial as to whether this type of exercise is suitable for children and adolescents because of the concern of safety and effectiveness for this age group.

Introduction

Strength training for adolescents is continually being researched and documented to refute these concerns and actually recommended as part of a growing individual’s exercise practices, particularly in females. One of the largest findings is the benefit it gives to an adolescent female’s bone mass density. Low bone mass density is one of the major causes of earlier than expected osteoporosis and increases the risk of fractures of major bones including the hip region, arms, and back, especially in postmenopausal women. The more an individual between the ages of six to 18 is exposed to resistance training, the higher their chances are of bone longevity and strength as they age.

Resistance Training and Bone Density in Adolescent Females

Obesity rates in children and adolescents have skyrocketed and with this, naturally, comes increased bone mass. However, bone mass does not equal bone strength or bone mass density. Adolescents that are overweight are at a particularly high risk for fracture and bone displacement, more than those that are not. But with this epidemic, resistance training, along with proper nutrition can be incredibly beneficial for not only health in general, but specifically bone health in their future. Developing healthy physical and dietary habits in adolescence decreases the chance of decline of bone mass density in aging. Nichols produced the study called “Resistance Training and Bone Mineral Density in Adolescent Females” and discovered that the major determinant of bone mass density is the bone mass gained in childhood and adolescence. He compiled a study that took 98 adolescent females and for nine months and for three sessions a week, trained all the major muscle groups using resistance training. It began with low weight, high reps, and two sets, and gradually increased to lower reps, heavier weight, and three sets. After the duration of the nine months, the study produced results of the females overall, gaining 85 percent bone mass density from the time that they started. They were expecting to see the greatest gain in the greater trochanter, but also saw significant results in the lumbar spine and femoral neck of the females. This study shows a total body increase in bone mass density by using resistance training as weekly physical activity. Nichols also discovered that most types of resistance exercises are relatively risk-free for increasing and maintaining bone mass density in female adolescents as there were no injuries in the process. He equates this to resistance exercises providing a more osteogenic effect than other forms of exercise such as solely walking or running. This study was performed on a large group of participants with a 78 percent compliance average over the nine month period. All of the participants were under the same criteria for acceptance including not being a part of varsity sports, engaging in activity more than two hours a week, and were between the ages of 14 and 17. Overall, this study seemed very well thought out and represented. The participants in the exercise group that had the greatest increases in femoral neck bone mass density had the lowest initial values. There is a question on whether or not this is because those individuals had reached their peak bone mass density during the course of the nine months or for other reasons. This poses a potential study question of determining at which age does peak bone mass occur and the individual differences between female adolescents.

Resistance training can frighten some of the population into not using it as an integral part of their chosen exercise regime. Especially in females, resistance training lacks in a workout program. Most females associate strength training with looking like a body builder and losing their femininity in the process to big and bulky muscles. This is, however, a huge myth that, by education and example, can be reversed. In the weight room, women usually gravitate toward cardio and core and disregard resistance training altogether. However, this will not yield the results that females are typically trying to achieve. As a future teacher, I need to be integrating this practice into my classes and teaching young adolescents that resistance training will not only give them benefits for the distance future, but also help reach their short term goals and prepare their bodies for their daily lives. I also want to teach by example. In my practicum experience, I am encouraged by the amount of participation I am seeing compared to the very first class I was there. My mentor teacher has shared with me that attendance rates for his classes have increased, and particularly females. He has said that he has had a difficult time trying to have his females engage with the course and since having me in the class, he has seen a huge change in his individual students. Not only are they attending class, but they are participating, asking questions, and engaging with the content. This is very encouraging for me to keep up my own program and explore deeper into training so I can have more knowledge that is readily available for times that I need it. Role models are huge for children and adolescents and I hold that as part of my job description as a future teacher. If resistance training is taught and worked on throughout adolescence, this will be giving them a crucial tool and foundation for a current and future healthy lifestyle.

Timing of Peak Bone Density in Females

Osteoporosis is an inevitability of aging, but the extent and quickness to which the bone density degenerates can be altered with beginning to strength train in adolescence. Matkovic wrote the article, “Timing of Peak Bone Mass in Caucasian Females and its Implication for the Prevention of Osteoporosis,” and defines osteoporosis as a deficiency of bone tissue relative to the volume of bone. He also adds that reduced bone density increases an individual’s susceptibility to fracture. This is the reason that the period of adolescence is important, because during this time is the period that most bone density can be acquired. During early-to-late adolescence, females’ bone density is still growing and they have yet to reach a point that continues no further. Adolescence is the time to gain as much bone density as possible before the peak of the individual is reached. Peak bone density is defined as the most bone density acquired as a result of normal growth. Peak bone density is important because together with loss due to age, it is one of the principal factors of determining bone density later in life, and also one of the factors that determines susceptibility to fracture. Thus, the phenomenon of resistance training in adolescence emerges as a crucial strategy for osteoporosis prevention. The more prevention tactics that are taken to maximize bone density during skeletal growth and development will minimize postmenopausal bone loss. In Matkovic’s study, he focused on the timing of an individual’s peak bone density. Peak bone density varies per individual, due to the interaction of heredity and endocrine factors as well as nutrition and physical activity factors. The results of his study showed that almost all of the sites that were recorded attained their peak bone density by late adolescence of age of 16 to 17. Approximately four percent per year between the pre-adolescent age of eight to nine and late adolescence of 16 to 17 is the time the most bone density will be accumulated. This is compared with the bone density growth between the ages of 18 and 50 which is only four percent. This is one of the results that supports accumulation of bone density growth during adolescence. An interesting finding in this study is the result of the bone density of females aging into adulthood. The slightly older women's bone density in the hip region, specifically, decreased rapidly. The maximum values of the hip bone density were found in the 17-year-old females. However, after the age of 17, that skeletal site already began to decrease in bone density. This suggests that the decline in the bone density of the proximal end of the femur begins immediately after the acquisition of peak bone mass. It would be interesting to discover if this is true for males as well, as studies seem to favour females in terms of the hip region. It would also be intriguing to see the amount in which an adult female’s hip bone density decreases with age and which elements contribute to that if continuing with strength training. Another possible furthering of this study could be on the discrepancy he explained in the time between the cessation of bone growth and bone density. He explains that the peak height of the participants was attained by the average age of 16. This indicated that a cessation of longitudinal bone growth was acquired by late adolescence. The timing of the cessation of longitudinal bone growth was one to seven years earlier than the cessation of the rapid accumulation of bone density at various skeletal sites. He describes that this time discrepancy indicates ongoing rapid consolidation of skeletal density after the bulk of bone modeling has been completed, but does not further explain.

For those that work with or are around adolescents daily, this is important knowledge to have. There is a window of time that is not usually taken advantage of for increasing bone density. After the peak bone mass is hit, the individual only decreases their bone density from there. Knowing that the peak bone density varies from individual to individual, this only hints at a deeper need for resistance training at this age. Adolescent females are especially in need of resistance training exposure at this time so they do not fall into the myths of women and strength training. As a future teacher, I see this as also an opportunity to teach about different body types and structure and make resistance training programs that are specific and expand their knowledge of variations. I want to teach, especially to females, that they can reap benefits from strength training and that the options are endless. This will keep it fun, interesting, and intriguing to hopefully encourage them internally to keep progressing and staying active in this way. If adolescents are exposed to this type of training at an early age, their bodies benefit from it immensely, but it also engages them into learning more and exploring so that resistance training stays relevant for them as an individual.

Milk and Calcium Intake and Greater Bone Density

In addition to strength training in adolescence for increase in bone density, nutrition, as in all fitness regimes, plays an enormous part. However, specific to this increase, is calcium intake. Teegarden complied a study called, “Previous Milk Consumption is Associated with Greater Bone Density in Young Women.” Her results were consistent with the hypothesis of the study that higher milk intake during adolescence is associated with increased total body, spine, and radial bone mineral density during development of peak bone mass. She discovered that adolescent milk intake was sufficient to predict bone density at several skeletal sites, suggesting that the measure of this study provided sufficient information. As this time period of adolescence is optimal for increasing bone density, it is crucial that calcium intake is also taken into the matter. Dietary calcium intakes decline from childhood to adolescence, leading to suboptimal intakes of calcium during this critical time period of building bone. The results of this study suggest that, although milk intake may decline from childhood to adolescence, the development of dietary habits that include the frequent intake of milk during childhood and adolescence is likely to lead to higher calcium intake in later years, which is beneficial. Teegarden did not account for those with allergies to lactose too much, however, Bonjour did and took calcium from milk extract and used it to fortify several daily food products in his study. This produced results that calcium-enriched foods given to adolescent females that did not consume the recommended daily allowance of calcium, significantly increased their bone density gain at several skeletal sites of skeleton. A question that this study proposes is if the recommended daily allowance is minimal or sufficient for this age group in their development. This would suggest a study that requires female adolescents of differing criteria to determine which amount of calcium intake is optimal for bone growth.

Nutrition plays an enormous role in a healthy lifestyle and, although usually very difficult, is well worth it. In general, nutrition is typically very interesting to people, but a lot of them have not been educated on it. Nutrition plays approximately an 80 percent role and exercise a 20 percent role in health. A lot of people actually reverse those numbers. They think that the more they exercise the more they will be healthy. However, a real truth is that people cannot beat poor nutrition with exercise. Exercise will only take an individual so far and usually the missing point is nutrition. This is the point at which individuals start to dislike exercise, because it does not give them results, so they stop. I have seen and heard this countless times and, unfortunately, it often becomes reality, even with encouragement to keep going. Personally, I have seen many adolescents in my practicum experience that like comfortability and familiarity. I like to push the boundaries a little bit with comfortability, while giving them familiarity. For example, I know some of my students hate squats; they think that they cannot do them because they “feel the burn” and quit. I try to somehow encourage them to keep trying and push themselves, because a lot of them do not know the extent to which their body is capable of doing certain exercises. The more I can encourage them to complete the time limit or the rep range, the more they become familiar. Thus, creating comfortability with the technique (not necessarily the exercise itself), and familiarity so they can do it on their own without me there. With some proper nutrition recommendations and strength training exercises, I hope to fill in the gaps of my students’ foundational knowledge of healthy habits and as they age, will benefit from being taught from a younger age.

Effects of Resistance Training on Adolescents

In consideration for the concern of safety in strength training in adolescents, Faigenbaum produced a study, “The Effects of Different Resistance Training Protocols on Muscular Strength and Endurance Development in Children.” He used a one rep maximum test in his study and found that it significantly increased both his exercise groups compared to his control group. So, showing that strength training by one rep maximums is safe for adolescence that are trained properly. Also, he discovered that gains resulting from high repetition and moderate load were significantly greater than that of low repetition and heavy load. Dhuig also agrees with Faigenbaum as his article states that adolescents should first participate in body weight training that is considered both safe and effective and through experience and knowledge can increase their intensity to 50% to 80% of their one rep maximum. Especially those of the ages 15 to18, this program seems to be beneficial. He suggests 1 to 3 sets per muscle group of 6 to 15 repetitions. This would put adolescent strength training similarly to that of an adult. These findings support the concept that muscular strength and bone density can be improved during the adolescent years and favour the implementation of higher repetition and moderate load resistance training programs for this age group. This study shows that adolescents can be privy to strength training and actually benefit greatly from it and not only for the present, but for the future as well.

There is a myth circling around this topic and, by research, has earned its title of being a myth. A lot of people believe that resistance training is dangerous and ineffective for adolescents and that this type of training is for adults only. However, children as early as ages seven and eight can start to resistance train and gain benefits from it. Benefits, not in terms of big muscles or massive strength, but appropriate strength for their age and foundational knowledge. This myth, means that a lot of students will be coming to me in high school not being taught anything about training or nutrition. This makes my job a lot more vast than just a physical education teacher. As other teachers teach math and science for foundational and functional knowledge, my students will also be taught foundational and functional knowledge. I have heard so many times, the bad reputations that physical education teachers have, and a lot of the time, they are unfortunately true. Gym is a time to “run around,” but my students will also learn in my class, the content that is just as important as math and science. Exercise naturally, as all things, needs to be tailored to students’ individual needs and abilities, but by starting this knowledge base early, adolescents will be able to balance their lives with healthy exercise habits, know the benefits, and how to integrate it into their daily lives as they age.

Conclusion

Contrary to the myth that resistance training is unsafe and ineffective for adolescents, it is actually both safe and effective for general health and also for prevention of chronic diseases such as osteoporosis as they age. Once creating a sound training foundation and using sensible progression, adolescents can increase their intensity and increase their bone density throughout these important years and enjoy the variation that strength training offers. Along with proper nutrition and conscious calcium intake, female adolescents can take advantage of the benefits of resistance training and protect their bodies from fracture and decrease the extent of osteoporosis.

References

Bonjour, Jean-Phillipe. (1997). Calcium-enriched Foods and Bone Mass Growth in Prepubertal Girls: A Randomized, Double-blind, Placebo-controlled Trial. PubMed Central. NCBI

Duhig, Steven John. (2013). STRENGTH TRAINING FOR THE YOUNG ATHLETE. Journal of Australian Strength and Conditioning.

Faigenbaum, Avery. (1999). The Effects of Different Resistance Training Protocols on Muscular Strength and Endurance Development in Children. Am Acad Pediatrics.

Matkovic, V., Jelic, T., Wardlaw, G. M., Ilich, J. Z., Goel, P. K., Wright, J. K., … Heaney, R. P. (1994). Timing of peak bone mass in Caucasian females and its implication for the prevention of osteoporosis. Inference from a cross-sectional model. Journal of Clinical Investigation, 93(2), 799–808.

Nichols, David, L. (2001). Resistance training and bone mineral density in adolescent females. Texas Woman’s University. Elsevier.

Teegarden, Dorothy. (1999). Previous milk consumption is associated with greater bone density in young women. American Society for Clinical Nutrition.