titian for a detailed nutrition plan, as this is outside the scope of practice for the fitness professional. Effective communication between the fitness professional ...
One on One
The One-On-One Column provides scientifically supported, practical information for personal trainers who work with apparently healthy individuals or medically cleared special populations. COLUMN EDITOR: Paul Sorace, MS, RCEP, CSCS*D
Programming Resistance Training for Clients With Type 2 Diabetes Mellitus Derek Grabert, MS, CSCS*D1 and Yuri Feito, PhD, MPH, RCEP, CES2 Physician Assistant Program, Drexel University, Philadelphia, Pennsylvania; and2Department of Exercise Science and Sport Management, Kennesaw State University Kennesaw, Georgia
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ABSTRACT IMPLEMENTING A RESISTANCE TRAINING PROGRAM FOR CLIENTS WITH TYPE 2 DIABETES POSES SOME DIFFICULTIES, BUT WITH THE PROPER DESIGN, THESE CLIENTS CAN ATTAIN SIGNIFICANT HEALTH AND FITNESS BENEFITS. RESISTANCE TRAINING PROGRAMS SHOULD BE PROGRESSIVE IN INTENSITY AND INDIVIDUALIZED FOR EACH CLIENT TO IMPROVE GLYCEMIC CONTROL, LEAN BODY MASS, AND STRENGTH.
he prevalence of type 2 diabetes mellitus (T2DM) has increased steadily over the past 15 years and has evolved into one of the most severe worldwide public health concerns (3). The accompanying Special Populations column covers the disease pathophysiology as well as the risks and benefits involved with exercise, with a specific focus on resistance training. This One-on-One column will provide
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a guide for fitness professionals to develop safe and effective resistance training programs for clients with T2DM, including recommended intensity, volume, mode, and progression. RESISTANCE TRAINING RECOMMENDATIONS
The American College of Sports Medicine (ACSM) and the American Diabetes Association (ADA) recently published standards on how to create a safe and effective exercise prescription for T2DM (5). Although a prescription for aerobic exercise was also included, this article will only discuss the resistance training component. The reader is encouraged to read more about the aerobic component by referring to Exercise and type 2 diabetes: the American College of Sports Medicine and the American Diabetes Association: joint position statement executive summary (5). With regard to resistance training, the ACSM/ADA recommends that clients with T2DM, cleared by their physician to participate in exercise, begin at an intensity of 50% 1 repetition maximum (1RM) or the
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intensity that allows a person to successfully complete 10–15 repetitions of an exercise (5). This moderate beginning intensity was consistent with previous published standards (1); however, the latter version advocates for more progressive increases in intensity to near 80% 1RM (5). This was in light of recent evidence, suggesting that high-intensity resistance training can elicit a significant improvement in glycemic control for persons with T2DM (2,6). These recommendations allow for progression to a level where noticeable improvements in fitness—namely increased strength and lean body mass—are made in addition to improved glycemic control (6). The initial fitness consultation should include completion of a medical history form and the Physical Activity Readiness Questionnaire and assumption of risk. Once medical clearance to participate in resistance training has been obtained from a physician, fitness professionals can begin designing a training program that is safe and effective for their client with T2DM. A discussion of basic nutrition within
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Table 1 Sample exercise progressions for management of type 2 diabetesa Novicea
Intermediate
Advanced
Leg curl
Deadlift
Goblet squat
Leg extension
Leg press
Deadlift
Bench press
Dumbbell chest press
Standing cable chest press
Upright row
Inverted row
Kneeling dumbbell row
Lateral pull-down
Assisted pull-up neutral grip
Assisted pull-up wide, pronated grip
Dumbbell seated shoulder press
Standing shoulder press
Dumbbell curl-to-press
Dumbbell seated biceps curl
Standing bicep curl
Dumbbell triceps kickback
Cable triceps press down
Dips (with/bench)
Abdominal curls
Planks
Combination (planks, crunches, V-sits)
a
Novice exercises were based on a progressive resistance training study that resulted in improved glycemic control among older adults with type 2 diabetes (6).
the fitness professional’s scope of practice is also important; however, the fitness professional should encourage the individual to seek out a registered dietitian for a detailed nutrition plan, as this is outside the scope of practice for the fitness professional. Effective communication between the fitness professional and client regarding blood glucose levels is imperative to avoid a hypoglycemic event. Clients may self-monitor their blood glucose, and the ACSM/ADA recommends that these individuals monitor before, sometimes during, and after exercise (5). Carbohydrate (CHO) snacks or drinks (likely containing 15–20 g of CHO) should be available in case of a hypoglycemic episode. Exercise testing should be performed to assess muscular strength. The 1RM strength test is not advised for untrained populations and other clients who have difficulty with exercise technique (7); therefore, a multiple RM testing (e.g., 10 RM) may be more appropriate for a novice client with T2DM. Anthropometrics (e.g., body fat testing) may need to be measured depending on client preferences and goals. Although this column focuses on resistance training, fitness professional must also be aware of clients’ aerobic capacity. Considering that T2DM increases a person’s likelihood of cardiovascular disease 2- to 4-fold
(4), it is recommended that most clients with T2DM undergo medically supervised electrocardiogram stress testing to determine appropriate intensity levels during both resistance and aerobic exercise (5). The accompanying Special Populations column addresses other contraindications and screening recommendations for clients with T2DM. PROGRAM DESIGN
The training program should include both short-term and long-term fitness goals to improve strength, lean body mass, and cardiorespiratory function. Improving medically related biomarkers of health such as blood pressure, glycemic response, and cholesterol should also be considered as goals of an exercise program; however, the fitness professional is not directly responsible for measuring these values and cannot control when they will be tested and evaluated. Therefore, the primary focus should be evaluation of fitness related outcomes, not clinical health outcomes. Overweight (body mass index [BMI] $ 25) or obesity (BMI $ 30) is present in approximately 80% of people with T2DM (9). Therefore, an exercise program for the management of T2DM should target weight loss (when needed) in addition to glycemic control. This can be achieved through resistance training, aerobic training, or a combination of
both. Progressive resistance training has the added benefit of increasing strength and lean body mass, which have both been positively correlated with improved glycemic control in persons with T2DM (2). The combination of aerobic and resistance training is considered the best strategy for managing T2DM (5,8). This column will not specifically outline an aerobic exercise training plan, but the ADA and ACSM recommend that medically cleared individuals with T2DM perform at least 150 minutes per week of moderate intensity aerobic exercise (5). Resistance training guidelines include exercise type, frequency, duration, intensity, volume, and rate of progression. Table 1 outlines 3 resistance training sessions—based on level of difficulty—for the management of T2DM. This table should serve as a guide, and fitness professionals are ultimately responsible for selecting the proper exercises and progressions for each client. For clients with T2DM, resistance training should be performed at least twice per week, incorporating 5–10 different exercises per session. The intensity should be moderate (50–60% 1RM) at the beginning and progress over time to higher intensities (75–80% 1RM). Table 2 outlines suggested intensities over the course of
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Refers to Table 1 for progressions based on level of difficulty for resistance training exercises.
Repetition schemes are not aligned with traditional intensity values (7).
SUMMARY
c
Multiple RM tests may be more appropriate for novice clients; intensity should only be increased once the client has successfully achieved the goal.
a 6-month resistance training program. It should be noted that some clients will progress faster or slower than the suggested goal intensities presented in Table 2. Volume will range anywhere from 1 to 4 sets of 8–15 repetitions or greater depending on the prescribed intensity. A combination of free weights and machines is appropriate. Machines may be used more frequently among clients with certain comorbidities. For example, ground-based exercises with a wide base of support (e.g., back squats) may be contraindicated for clients experiencing peripheral neuropathy (loss of sensation in feet). An alternative would be a combination of leg extensions and leg curls to target the quadriceps and hamstrings. There are currently no recommendations that advocate for either multi-joint or single-joint exercises; therefore, a combination of both types is considered optimal.
b
1RM 5 1 repetition maximum.
a
Make modifications Make modifications as necessary as necessary Revaluate multiple Evaluate if novice, intermediate, or RM (or 1RM advanced when progression is appropriate) appropriatec Evaluate if novice, Evaluate if novice Make intermediate, or intermediate modifications or advanced progression is as necessary progression more is appropriatec appropriatec Additional notes
8–10 8–10 8–10 Goal repetitionsb
10–15
8–12
8–12
8–10
80% 75% 70% 65% Goal intensity (based on %1RM)a
50%
55%
60%
20 16 12 8 4 Week
1
Table 2
Resistance training intensity guidelines for management of type 2 diabetes
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One on One
Fitness professionals are responsible for implementing safe and effective resistance training programs for clients with T2DM, whereas motivating clients to achieve desired fitness outcomes. This requires taking an individualized approach to account for each client’s comorbidities and exercise contraindications. Furthermore, resistance training should be progressive in mode and intensity for each client with T2DM. Conflicts of Interest and Source of Funding: The authors report no conflicts of interest and no source of funding. Derek Grabert is an educational content coordinator at the National Strength and Conditioning Association World Headquarters. Yuri Feito is an assistant professor at Kennesaw State University in the Department of Exercise Science and Sport Management. REFERENCES 1. Albright A, Franz M, Hornsby G, Kriska A, Marrero D, Ullrich I, and Verity LS. American College of Sports Medicine position stand. Exercise and type 2 diabetes. Med Sci Sports Exerc 32: 1345–1360, 2000.
2. Castaneda C, Layne JE, Munoz-Orians L, Gordon PL, Walsmith J, Foldvari M, Roubenoff R, Tucker KL, and Nelson ME. A randomized controlled trial of resistance exercise training to improve glycemic control in older adults with type 2 diabetes. Diabetes Care 25: 2335–2341, 2002. 3. Centers for Disease Control and Prevention. Diabetes successes and opportunities for population-based prevention and control at a glance 2011. Available at: http://www.cdc. gov/chronicdisease/resources/publications/ AAG/ddt.htm. Accessed August 12, 2012. 4. Centers for Disease Control and Prevention. 2011 National Diabetes Fact Sheet: National estimates and general information on diabetes and prediabetes in the United
States. Available at: http://www.cdc.gov/ diabetes/pubs/factsheet11.htm. Accessed November 15, 2012. 5. Colberg SR, Sigal RJ, Fernhall B, Regensteiner JG, Blissmer BJ, Rubin RR, Chasan-Taber L, Albright AL, and Braun B. Exercise and type 2 diabetes: The American College of Sports Medicine and the American Diabetes Association: Joint position statement executive summary. Diabetes Care 33: 2692–2696, 2010. 6. Dunstan DW, Daly RM, Owen N, Jolley D, De Courten M, Shaw J, and Zimmet P. Highintensity resistance training improves glycemic control in older patients with type 2 diabetes. Diabetes Care 25: 1729–1736, 2002.
7. Haff GG and Haff EE. Resistance training program design. In: NSCA’s Essentials of Personal Training. Coburn JW and Malek MH, eds. Champaign, IL: Human Kinetics, 2012. pp. 347–388. 8. Maiorana A, O’Driscoll G, Cheetham C, Dembo L, Stanton K, Goodman C, Taylor R, and Green D. The effect of combined aerobic and resistance exercise training on vascular function in type 2 diabetes. J Am Coll Cardiol 38: 860–866, 2001. 9. National Diabetes Information Clearinghouse, US Department of Health and Human Services. Diabetes overview. Available at: http://diabetes.niddk.nih.gov/ dm/pubs/overview/index.aspx. Accessed November 8, 2012.
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