- Increases bone density (Hurley 1994)
- Increases glucose uptake (Hurley 1994)
- Increases gastrointestinal transit time (Koffler 1992)
- Improved HDL levels (Stone 1982, Hurley 1988)
- Reduced resting blood pressure (Harris 1987)
- effects of weight training equal to aerobic exercise (Westcott 1995)
- Reduced low back pain (Risch 1993)
- requires isolated low back strength training
- Reduced osteoarthritis and rheumatoid arthritic pain (Tufis 1994)
- Reduced depression (Signh 1997)
Men and women reach peak strength around 20 to 25 years of age. After age 25, strength generally decreases an average of 1% per year. Therefore, a 65-year-old would only have about 60% of the strength they had at age 25. Individuals who are more active, or those who continue to strength train, can considerably decrease this tendency for declining muscular strength.
Strength training for older adults can reverse the loss of muscle mass and enhance their ability to perform activities of daily living.
Welle S. Resistance training in older persons. Clinical Geriatrics 1998;6 (1):48-59.
Radakovich J. Prescribing resistance training for elderly patients. Your Patient and Fitness 1997;11(2):27-30.
A muscle's strength has a strong relationship with its cross sectional area in both men and women. Muscle enlargement with a corresponding increase in strength was first shown scientifically as early as 1897.
Ikai M, Fukunaga T, Calculation of muscle strength per unit cross-sectional area of human muscle by means of ultrasonic measurements. Int Z Angew Phsiol, 26:26-32, 1968.
Hetting T: Physiology of Strength. Springfield. Ill, C. C Thomas, 1961.
Morpurgo B: U:ber Aktivita:ts-Hypertrophie der willkurlichen Muskeln. Virchows Arch. Pathol Anat Physiol, 150:522-544, 1897.
Strength recovery was noted in an early exercise physiology textbook. Elbow flexors were tested for strength and were worked to exhaustion.
- 69% of strength was regained after 30 seconds of recovery
- 82% of strength was regained after 2.5 minutes
- 87% of strength was regained after 7.5 minutes
- 95% of strength was regained after 42.5 minutes
- only 26% more than what had been regained after a 30 second rest
Morehouse LE, Augustus TM (1971), Physiology of exercise, The C.V. Mosby Company, Saint Lois, 6th Ed, pg 60.
Combined Muscular Strength
It is estimated that if all the muscles of the human body work together, it could lift 11 tons, the equivalent of 4 SUVs.
Heavy resistance training can stimulate hypertrophy of both Type I and II fibers, with Type II fiber experiencing the greatest rate of hypertrophy. Also see Fiber Type Comparison.
Gonyea & Sale 1882; Hakkinen & Komi 1985; Hakkinen, et al 1989; MacDougall et al. 1980; Thorstensson 1976.
Heavy resistance training leads to both sarcoplasmic and myofibrillar hypertrophy. Sarcoplasmic Hypertrophy is an increased volume of sarcoplasmic fluid (Semifluid interfibrillar substance) in the muscle cell that does not directly contribute to the production of muscular force. Myofibrillar Hypertrophy is an increase in the number of actin and myosin contractile proteins resulting in muscular strength with a small increase in muscular size.
Sarcoplasmic hypertrophy is more dominant in the muscles of bodybuilders while myofibrillar hypertrophy is greater in Olympic weightlifters (Zatsiorsky & Kraemer, 1995). Contributing factors include both type of training performed and affinity to a respective sport favoring those with particular genetic predispositions. Those who start and continue in a particular sport tend to have genetic attributes that are conducive to their chosen endeavor and train accordingly.
Zatsiorsky VM, Kraemer WJ (1995). Science and Practice of Strength Training. 2nd Ed, 50., Human Kinetics Publishers
Strength training increases neuromuscular efficiency
- Increased number of motor units recruited
- Increased firing rate of each motor unit
- Increased synchronization of motor unit firing
Also see Motor Development.
Resistance training incorporating high-volume, moderate-intensity, and short rest periods, may increase capillarization in the muscles (Schantz 1982; Tesch, et al. 1984). Bodybuilders who typically perform this sort of training were able to exercise at a higher percentage of their 1 rep max for 3 sets of 10 repetitions, compared to powerlifters when plasma lactate concentrations were equally elevated in both groups (Kreamer et al 1987).
Reps Variations with Percentage of One Rep Max
The actual number of repetitions performed with a percentage of a one rep max (1RM) varies widely, depending the muscle groups exercised, exercise performed, and population tested. Hoeger (1990) reported trained females performed 22.4 reps (+/- 10.7 reps) with 80% of their 1RM on the Leg Press, whereas untrained females performed 11.9 reps (+/- 7 reps). On the Leg Curl, both groups only performed 5.3 and 5.9 reps respectively (+/- 2.6 reps) with 80% of their 1RM. On the Bench Press, trained females performed 14.3 reps (+/- 4.4 reps) of their 1RM, whereas untrained males performed only 9.8 reps (+/- 3.6 reps). On the Arm Curl, trained men performed 11.4 reps (+/-4.15 reps) whereas untrained females performed only 5.9 reps (+/- 3.6 reps). Larger muscle group exercises appear to need higher percentages of 1RM to stay within a given repetion zone. Also see One Rep Max Calculator.
Hoeger WWK, Hopkins DR, Barette SL, Hale DF (1990). Relationship between repetitions and selected percentages of one repetition maximum: a comparison between untrained and trained males and females. Journal of Strength and Conditioning Research. 4(2):47–54.
Relatively newer exercises for core strength and balance such as standing on a balance pad with one leg and bending forward to touch the floor have been criticized as being unnecessarily risky, ineffective, and laughable by at least some top training coaches (Bompa & Carrera 2015). These newer exercises for core strength are not necesssary because many traditional weight training exercises already strengthen the core more effectively via overflow of activation (Enoka 2002, Zijdewind & Kernell 2001). Also see Balance, Equilibrium, and Stability and Are Sit-ups Safe?.
Bompa T, Carrera M (2015) Conditioning Young Athletes. Human Kinetics.
Enoka R (2002) Neuromechanics of Human Movement, 3rd Ed. Human Kinetics.
Zijdewind I, Kernell D (2001). Bilateral interactions during contractions of intrinsic hand muscles. Journal of Neurophysiology. 85(5):1907-1913.
Strength Training for Swim Performance
Few studies demonstrated the efficacy of weight training on freestyle (front crawl) swimming performance. Aspenes et. al 2009 showed that two weekly sessions of weight training designed to imitate the butterfly stroke improve tethered freestyle swimming force. It also improved 4 distance performance but did not improve 50 and 100 m performance.
Aspenes S, Kjendlie PL, Hoff J, Helgerud J (2009). The combined strength and endurance training in competitive swimmers. J Sports Sci Med. 1;8(3):357-65.
Strength gains from a particular exercise or movement may temporarily enhance strength gains of other exercises for similar or even adjacent movements.
Introduction of Weighted Chest Dips may increase strength in Bench Press, Incline Bench Press, and Shoulder Press.
The introduction of Pullover may increase Chin-up strength. The increased strength for Chin-ups may also, in turn, increase strength for more remotely related exercises such as Chest Dips, Bench Press, or Arm Curls.
Although the movements are not exactly the same, common muscles are involved with these different movements. This phenomenon would suggest that a particular new exercise added to a workout may indirectly increase strength gains for other more commonly performed exercises, even seemingly unrelated movements.
Approximately 20 million women in the United States are affected by osteoporosis, leading to multiple fractures and increased hospitalizations.
Boning up on osteoporosis: a guide to prevention and treatment. Washington, D.C.: National Osteoporosis Foundation, 1991.
Resistance training has been shown repeatedly to increase bone marrow density, which can decrease the morbidity and mortality resulting from osteoporosis.
Hamdy R., Anderson J, Whalen K, Harvill L. Regional differences in bone density of young men involved in different exercises. Medicine and Science in Sports and Exercise 1994; 26: 884-888.
Heinonen A, Oja P, Kannus P, Sievanen H, Manttari A, Vuori I. Bone mineral density of female athletes in different sports. Bone and Mineral 1993;23:1-14.
Karlson M., Johnell O. Obrant K. Bone mineral density in weightlifters. Calcified Tissue International. 1993;52:212-215.
Nelson ME, Fiatarone MA, Morganti CM, Trice I, Greenberg RA, Evans WJ. Effects of high intensity strength training on multiple risk factors for osteoporotic fractures. A randomized controlled trial. JAMA 1994;272(24):1909-1914.
Pocock NA, Eisman J, Gwinn T, Sambrook P, Kelly P, Freund J, et al. Muscle strength, physical fitness, and weight but not age to predict femoral neck bone mass. Journal of Bone and Mineral Research 1989;4(3):441-448.
Menkes A, Mazel S, Redmond RA, Koffler K, Libanati CR, Gundberg CM, et al. Strength training increases regional bone mineral density and bone remodeling in middle-aged and older men. Journal of Applied Physiology 1993; 74(5):2478-2484.
"The original dumbbell was an apparatus contrived like that for ringing church-bells; that is, a heavy fly-wheel with a weight attached, which was set in motion like a church-bell, until it acquired sufficient impetus to carry the gymnast up and down, and so bring the muscles into active play. There is one at New College, Oxford, to the present day. The modern weights, so-called, produce similar results, in a less cumbrous and more agreeable manner." - Edwards' Words, Facts, and Phrases.
Phyfe WHP (1901) Five Thousand Facts and Fancies, GP Putnam's Sons, pg 250.
Many people have heard of Author Jones (1926 - 2007), the creator of Nautilus exercise machines, but few today have heard of the exercise machines of Dr. Gustav Zander, 100 years earlier. Jonas Gustav Vilhelm Zander (1835-1920) was a Swedish physician and orthopedist, who in 1879 created several weight training machines that used special-shaped cams to provide muscular tension through a full range of motion (sound familiar?). By 1906, he established Institutes throughout the world, in 146 countries. His exercise machines were also found in health spas throughout the western world and were widespread in the US in the early 20th century. Jones insisted that he developed and designed Nautilus machines without any knowledge of Zander's inventions.
In 1875, Nipher academic paper relating to muscular performance in work was published in America's first scientific journal. The journal article mentions strength adaptation, daily work volume (kgr.-meters), dynamometer, and differentiates 'static work' versus 'dynamic work'. Nipher also later published a study on a form of serial positioning effect.
FE Nipher, Assistant Professor of Physics at Washington University (1875). On the Mechanical work done by a muscle before exhaustion. American Journal of Science and Arts. 9(100), 130-137.