In Prevention of Bone Loss Resistance exercise has a more profound site-specific effect than aerobic exercise (even swimming and biking) Layne JE, Nelson ME: The effects of progressive resistance training on bone density: a review. Med Sci Sports Exerc 1999;31(1):25-30
Early Research Studies Erich Mueller & Theodor Hettinger, German scientist (1953, 1955) who formalize isometric training concepts by having their research studies published in academic journals Studies showed that 1 daily effort, 2/3 max exertion for 6 sec. will increase strength about 5% per week Clark et al (1954) found static strength continues to increase even after the conclusion of a 4 week program of isometric exercises
Isometric progressive resistive exercise for osteoporosis. Swezey RL, Swezey A, Adams J., J Rheumatol 2000 Dec;27(12): OBJECTIVE: To assess the effect of site-specific resistive isometric exercises on muscle strengthening of 10 muscle groups over 2 months. A second study measured bone alkaline phosphatase (ALP) as a marker of bone formation and bone resorption in a similar cohort. CONCLUSIONS: Brief progressively resisted isometric exercises for 10 min daily are an adequate stimulus for muscle strengthening of the neck, back, upper and lower extremities, and are capable of enhancing bone formation measured by bone ALP.
Programming Recommendations Early Recommendations based off Hettinger & Muller, Research (1954) – One-6 second isometric contraction (slightly more for well-trained athletes) – 2/3 maximum – Performed once each day for five days – Sufficient for 5% strength gains per week
Effectiveness in Strength Development Force created by holding a contraction position causes the body to recruit & activate a continuous increase in motor units to maintain the contraction The motor units recruited are forced to continuously contract with no major decrease in force output Muscles reach maximum contraction effectively, thus entire muscle fatigues quickly Muller, E.A. (1970) Influence of Training and of Inactivity on Muscle Strength, Archives of Physical Medicine and Rehabilitation, Vol. 51, August, Mueller, E.A. & Rohmert W., The rate of increase in muscular strength during isometric training. Int Z Angew Physiol. 1963;19:
In Arthritis Patients Isometric exercise is often prescribed because it appears to be less damaging to inflamed and damaged joints It has been shown that isometric strengthening can lead to ADL performance with reduced effort and an increase in V 02max, Galloway MT, Jokl P. The role of exercise in the treatment of inflammatory arthritis. Bull Rheum Dis 42(1):1-7, 1993.
Isometrics and Osteoarthritis Several studies have specifically investigated the difference between isotonic, isokinetic and isometric options in relation to training people with osteoarthritis. In these cases isometric training was found significantly and in some cases equally effective in reducing pain and/or improving functional ability (Cheing et al., 2002; Ekdahl et al., 1990; Huang et al., 2003; Marks, 1994; Miyaguchi et al., 2003; Topp et al., 2002).
The effect of dynamic versus isometric resistance training on pain and functioning among adults with osteoarthritis of the knee. Topp R, Woolley S, Hornyak J 3rd, Khuder S, Kahaleh B., Arch Phys Med Rehabil Sep;83(9): OBJECTIVE: To compare 16 weeks of isometric versus dynamic resistance training versus a control on knee pain and functioning among patients with knee osteoarthritis (OA). CONCLUSION: Dynamic or isometric resistance training improves functional ability and reduces knee joint pain of patients with knee OA. The improvements in the 2 training groups as a result of their respective therapies were not significantly different. The control group did not change over the duration of the study.
Isometrics in Therapy Isometrics stress the muscle without joint movement, reducing stress on the tendons, fascia, etc. Exact area of muscle weakness can be isolated Strengthening can be administered at the proper joint angle Provides a relatively quick and convenient method for overloading and strengthening muscles without expensive equipment J Am Geriatr Soc 2001, Exercise prescription for older adults with osteoarthritis pain: consensus practice recommendations. 49(6):
Isometrics Post Injury Rehabilitation for any joint usually progresses through several phases When ROM is limited, mild isometrics are prescribed in an effort to maintain tone & increase ROM at end range Exercises can be performed in joint positions that produce no pain or excessive stress, which avoids jeopardizing the healing process of the injury Baechle Essentials of Strength and Conditioning Human Kinetics.
Importance of isometric training in the rehabilitation of myocardial infarct patients. Bokebaeva RT., Kardiologiia Jul;26(7): The efficacy of isometric training during hospitalized rehabilitation in patients with myocardial infarction. Alekperov EZ, Rustamov ChI, Mamedov EA., Kardiologiia Oct; 31(10):30-1. OBJECTIVE: The objective of this research was to study the effect of isometric training in the rehabilitation of myocardial infarct patient CONCLUSIONS: It was concluded that isometric exercise has a favorable effect on cardiovascular function and physical working capacity of postmyocardial-infarction patients.
Isometric training lowers resting blood pressure and modulates autonomic control. Taylor AC, McCartney N, Kamath MV, Wiley RL., Med Sci Sports Exerc Feb;35(2): Isometric exercise training lowers resting blood pressure. Wiley RL, Dunn CL, Cox RH, Hueppchen NA, Scott MS., Med Sci Sports Exerc Jul;24(7): Isometric handgrip training reduces arterial pressure at rest without changes in sympathetic nerve activity. Ray CA, Carrasco DI. Am J Physiol Heart Circ Physiol. 2000; 279(1):H OBJECTIVE: These studies examined the effects of isometric handgrip training on resting arterial blood pressure, heart rate variability, and blood pressure variability in older adults with and without hypertension. CONCLUSIONS: In all of the studies results indicate that IHG training is an effective nonpharmacological intervention in lowering resting blood pressure
Programming Possibilities Prehab/Rehab – Angle specific – Progressing duration – Progressive intensity General Fitness – Progressing duration – Progressive intensity – Multi range and/or repetitions – Integrated conditioning Sport Enhancement – Angle specific – Rate specific
American Geriatric Society (AGS) Clinical Practice Committee and Board of Directors Recommendations Exercises : Involve all major muscle groups Frequency : Once to Twice daily – Number of exercises can be gradually increased, as tolerated Intensity : Initial training intensity 30% of max effort – Gradually increase to 75% MVC as tolerated
Isometrics Revisited Summary of Advantages Increases in muscle and bone mass Achieves max contraction with minimal joint stress Allows strength gains in specific muscle that are weak Non-intimidating for beginning, and/or inactive people Ideal for persons with joint limitations or pain May aid in sports performance Workout takes minimal time to complete Workout needs no or minimal equipment and can be done anywhere