Acute Variables: Training Load (Weight and Resistance)

This course discusses the optimal load (a.k.a. weight, resistance, or intensity) for strength training, including the optimal weight for the goals of enhancing strength (e.g. 1 repetition maximum strength, or 1-RM strength), strength endurance (e.g. increasing repetitions to failure), hypertrophy (e.g. muscle growth), and power (e.g. increased velocity and athletic performance). Further, optimal weight recommendations are discussed based on training experience, including novice exercisers, experienced exercisers, athletes, children, and elderly exercisers. Additional topics include the effects of training load on blood chemistry, hormones, markers of muscle growth, cardiovascular changes, bone mineral density, body composition (body fat), electromyography, and rate of perceived exertion (RPE).

Some findings from the included systematic research review resulted in counter-intuitive, or at least less conventional recommendations. For example, endurance strength is likely specific to load (and exercise), training with very heavy loads (1-2 RM/set) may be less effective for improving strength, and training load is likely less influential than performing reps-to-failure/set or increasing training volume for increasing muscle mass (hypertrophy). Additionally, the relationship between acute variables is discussed; for example, the "right weight" when planning a strength training block with conventional repetition tempos, for an athlete that has a primary goal of increasing power (e.g. speed or vertical jump height).

Movement professionals (personal trainers, fitness instructors, physical therapists, athletic trainers, massage therapists, chiropractors, occupational therapists, etc.) should consider acute variables essential knowledge for optimal exercise programming, and training load as one of those acute variables. This course is part of our continued effort to optimize “acute variable” recommendations.

Pre-approved credits for:

• Certified Personal Trainer (CPT) Certification

Pre-approved for Continuing Education Credits for:

• Athletic Trainers
• Chiropractors
• Group Exercise Instructors
• Massage Therapists
• Occupational Therapists - Intermediate
• Personal Trainers
• Physical Therapists
• Physical Therapy Assistants
• Physiotherapists

This Course Includes:

• AI Tutor
• Course Summary Webinar
• Study Guide
• Text and Illustrations
• Audio Voice-over
• Research Review
• Technique Videos
• Case Study and Sample Routine
• Practice Exam
• Pre-approved 4 Credit Final Exam

Additional Courses:

• Acute Variables: Repetition Tempo
• Acute Variables: Repetition Range
• Acute Variables: Rest Between Sets
• Acute Variables: Circuit Training
• Acute Variables: Sets per Muscle Group
• Acute Variables: Training Frequency and Recovery Between Sessions

Load Definitions

Based on the methodologies in the research cited in this review.

• Very Heavy: 1-2 RM/set (95 - 100% of 1-RM)
• Heavy: 3 - 8 RM/set (80 - 95% of 1-RM)
• Moderate: 8 - 12 RM/set (70 - 80% of 1-RM)
• Light: 12 - 25 RM/set (50 - 70% of 1-RM)
• Very Light: 25 or more RM/set (50 % of 1-RM or Less)

*RM = repetition (rep) maximum. The maximum number of reps performed before failure (fatigue).

Position Statement: Optimal Training Load (Weight)

• Moderate and heavy loads are likely optimal for most training goals. Moderate and heavy training loads are recommended, and likely the most influential variable for improving strength, with very heavy, light, and very light loads resulting in less or no improvement. Additionally, moderate and heavy loads are likely optimal for improving hypertrophy; however, the load is likely less influential than performing reps-to-failure/set and total training volume. Very light loads with explosive tempos are likely ideal for increasing power (velocity); however, heavier loads result in larger power improvements than lighter loads when comparing strength training with conventional repetition tempos (moderate or slow). Endurance strength is specific to load, and training should aim to increase reps-to-failure/set with a goal/activity-specific load. Last, novice, older, and younger populations should begin training with light or moderate loads, and progress to heavy load training. In summary, cycles of moderate and heavy load training are likely ideal for most training goals. Light and very light loads may only be appropriate for some novice exercisers, while power training with explosive tempos, and/or for some strength endurance goals. Very heavy loads should be reserved for 1 RM practice, and should not be included in regular strength training routines.

Goal-based Recommendations

• Endurance: Light loads (or load-specific)
• Strength: Moderate and heavy loads
• Power: Light loads and very light loads with ballistic tempos (heavy loads during conventional strength training)
• Hypertrophy: Moderate and heavy loads (training volume may be more influential)
• Older Individuals and Children: Light and moderate loads, progressing to heavy loads
  • Load recommendations assume the performance of reps-to-failure/set.

Sample Program

Experienced Exerciser:

• Goal: Strength
• Split: Full body
• Frequency: 2 - 3 sessions/week
• Routine Construction: Circuit Training
• Periodization: 2-phase block periodization

Phase 1 (4 - 8 weeks):

Acute Variables

• Load: Moderate (70-80% of 1-RM)
• Reps/set: 8-12 reps
• Sets/exercise (circuits): 2-3sets/muscle  group
• Rest between exercises: Circuit training, 1 min rest between exercises
• Training Time: 25 – 45 minutes (excluding warm-up).

Routine

• Legs
  
  • Back squats
• Chest:
  • Incline alternating dumbbell chest press
• Back:
  • Horizontal pull-up
• Shoulders:
  • Curl-to press
• Corrective (Active Rest)
  • Standing Cobra

Phase 2 (4 - 8 weeks):

Acute Variables

• Load: Heavy (80 - 95% of 1-RM)
• Reps/set: 3-8 reps/set
• Sets/exercise (circuits): 3-4 sets/muscle  group
• Rest between exercises: Circuit training, 1 min rest between exercises
• Training Time: 25 – 45 minutes (excluding warm-up).

Routine

• Integrated Exercise
  
  • Front Squat to Press
• Back:
  • Pull-up
• Chest:
  • Bench Press
• Legs:
  • Barbell deadlifts with posterior pull
• Corrective (Active Rest):
  • Standing Cobra to Balance to Calf Raise

Training Load and Blood Chemistry

1. Fink, J., Kikuchi, N., & Nakazato, K. (2016).Effects of rest intervals and training loads on metabolic stress and muscle hypertrophy. Clinical physiology and functional imaging, 38(2), 261-268
2. Hakkinen, K., & Pakarinen, A. (1993).Acute hormonal responses to two different fatiguing heavy-resistance protocols in male athletes. Journal of Applied Physiology, 74(2), 882-887.
3. Schwab, R. O. B. E. R. T., Johnson, G. O., Housh, T. J., Kinder, J. E., & Weir, J. P. (1993). Acute effects of different intensities of weight lifting on serum testosterone. Medicine and science in sports and exercise, 25(12), 1381-1385.
4. Kraemer, W. J., Marchitelli, L., Gordon, S. E., Harman, E., Dziados, J. E., Mello, R., ... & Fleck, S. J. (1990). Hormonal and growth factor responses to heavy resistance exercise protocols. Journal of Applied Physiology, 69(4), 1442-1450.
5. Kraemer, W. J., Fleck, S. J., Dziados, J. E., Harman, E. A., Marchitelli, L. J., Gordon, S. E., ... & Triplett, N. T. (1993).Changes in hormonal concentrations after different heavy-resistance exercise protocols in women. Journal of applied physiology, 75(2), 594-604
6. Zafeiridis, A., Smilios, I., Considine, R. V., & Tokmakidis, S. P. (2003). Serum leptin responses after acute resistance exercise protocols. Journal of Applied Physiology, 94(2), 591-597.
7. Smilios, I., Pilianidis, T., Karamouzis, M., & Tokmakidis, S. P. (2003). Hormonal responses after various resistance exercise protocols. Medicine & Science in Sports & Exercise, 35(4), 644-654.
8. Raastad, T., Bjøro, T., & Hallen, J. (2000). Hormonal responses to high-and moderate-intensity strength exercise. European journal of applied physiology, 82, 121-128.
9. Burd, N. A., West, D. W. D., Staples, A. W., Atherton, P. J., Baker, J. M., Moore, D. R., Holwerda, A. M., Parise, G., Rennie, M. J., Baker, S. K., and Phillips, S. M. (2010) Low-load high volume resistance exercise stimulates muscle protein synthesis more than high-load low volume resistance exercise in young men. PLoS ONE, 5(8), doi: 10.1371/journal.pone.0012033f
10. Morton, R. W., Oikawa, S. Y., Wavell, C. G., Mazara, N., McGlory, C., Quadrilatero, J., ... & Phillips, S. M. (2016). Neither load nor systemic hormones determine resistance training-mediated hypertrophy or strength gains in resistance-trained young men. Journal of Applied Physiology, 121(1), 129-138.
11. Popov, D. V., Swirkun, D. V., Netreba, A. I., Tarasova, O. S., Prostova, A. B., Larina, I. M., ... & Vinogradova, O. L. (2006). Hormonal adaptation determines the increase in muscle mass and strength during low-intensity strength training without relaxation. Human Physiology, 32(5), 609-614.
12. Holm, L., Reitelseder, S., Pedersen, T. G., Doessing, S., Petersen, S. G., Flyvbjerg, A., ... & Kjaer, M. (2008). Changes in muscle size and MHC composition in response to resistance exercise with heavy and light loading intensity. Journal of Applied Physiology, 105(5), 1454-1461.
13. Holm, L., Van Hall, G., Rose, A. J., Miller, B. F., Doessing, S., Richter, E. A., & Kjaer, M. (2009). Contraction intensity and feeding affect collagen and myofibrillar protein synthesis rates differently in human skeletal muscle. American Journal of Physiology-Endocrinology and Metabolism
14. Mitchell, C. J., Churchward-Venne, T. A., West, D. W., Burd, N. A., Breen, L., Baker, S. K., & Phillips, S. M. (2012). Resistance exercise load does not determine training-mediated hypertrophic gains in young men. Journal of Applied Physiology, 113(1), 71-77.
    Load and Cardiovascular Changes
15. Tanimoto, M., Sanada, K., Yamamoto, K., Kawano, H., Gando, Y., Tabata, I., ... & Miyachi, M. (2008). Effects of whole-body low-intensity resistance training with slow movement and tonic force generation on muscular size and strength in young men. The Journal of Strength & Conditioning Research, 22(6), 1926-1938.
16. Hunter, G. R., Seelhorst, D., & Snyder, S. (2003). Comparison of metabolic and heart rate responses to super slow vs. traditional resistance training. The Journal of Strength & Conditioning Research, 17(1), 76-81.
17. Mazzetti, S., Douglass, M., Yocum, A., & Harber, M. (2007). Effect of explosive versus slow contractions and exercise intensity on energy expenditure. Medicine and science in sports and exercise, 39(8), 1291.
18. Hatfield, D. L., Kraemer, W. J., Spiering, B. A., Häkkinen, K., Volek, J. S., Shimano, T., ... & Maresh, C. M. (2006). The impact of velocity of movement on performance factors in resistance exercise. The Journal of Strength & Conditioning Research, 20(4), 760-766.
19. Au, J. S., Oikawa, S. Y., Morton, R. W., MacDonald, M. J., & Phillips, S. M. (2017). Arterial Stiffness Is Reduced Regardless of Resistance Training Load in Young Men. Medicine and science in sports and exercise, 49(2), 342-348.
20. KEELER, L. K., FINKELSTEIN, L. H., MILLER, W., & Fernhall, B. O. (2001). Early-phase adaptations of traditional-speed vs. superslow resistance training on strength and aerobic capacity in sedentary individuals. The Journal of Strength & Conditioning Research, 15(3), 309-314.
21. Netreba, A. I., Popov, D. V., Bravyi, Y. R., Misina, S. S., & Vinogradova, O. L. (2009). Physiological effects of low-intensity strength training without relaxation. Human physiology, 35(4), 479-483.
22. Rana, S. R., Chleboun, G. S., Gilders, R. M., Hagerman, F. C., Herman, J. R., Hikida, R. S., ... & Toma, K. (2008). Comparison of early phase adaptations for traditional strength and endurance, and low-velocity resistance training programs in college-aged women. The Journal of Strength & Conditioning Research, 22(1), 119-127.
23. Campos, G. E., Luecke, T. J., Wendeln, H. K., Toma, K., Hagerman, F. C., Murray, T. F., ... & Staron, R. S. (2002). Muscular adaptations in response to three different resistance-training regimens: specificity of repetition maximum training zones. European Journal of Applied Physiology, 88(1), 50-60.
    Load and Electromyographic (EMG) Activity (and 15 & 21)
24. Looney, D. P., Kraemer, W. J., Joseph, M. F., Comstock, B. A., Denegar, C. R., Flanagan, S. D., ... & Maresh, C. M. (2016). Electromyographical and perceptual responses to different resistance intensities in a squat protocol: does performing sets to failure with light loads produce the same activity? The Journal of Strength & Conditioning Research, 30(3), 792-799
25. Gonzalez, A. M., Ghigiarelli, J. J., Sell, K. M., Shone, E. W., Kelly, C. F., & Mangine, G. T. (2017). Muscle activation during resistance exercise at 70% and 90% 1‐repetition maximum in resistance‐trained men. Muscle & Nerve, 56(3), 505-509.
26. Jenkins, N. D., Housh, T. J., Bergstrom, H. C., Cochrane, K. C., Hill, E. C., Smith, C. M., ... & Cramer, J. T. (2015). Muscle activation during three sets to failure at 80 vs. 30% 1RM resistance exercise. European Journal of Applied Physiology, 115(11), 2335-2347.
27. Schoenfeld, B. J., Contreras, B., Willardson, J. M., Fontana, F., & Tiryaki-Sonmez, G. (2014). Muscle activation during low-versus high-load resistance training in well-trained men. European journal of applied physiology, 114(12), 2491-2497.
28. Schoenfeld, B. J., Contreras, B., Vigotsky, A. D., Ogborn, D., Fontana, F., & Tiryaki-Sonmez, G. (2016). Upper body muscle activation during low-versus high-load resistance exercise in the bench press. Isokinetics and Exercise Science, 24(3), 217-224.
29. Tanimoto, M., & Ishii, N. (2005). Effects of low-intensity resistance exercise with slow movement and tonic force generation on muscular function in young men. Journal of Applied Physiology, 100(4), 1150-1157.
30. McBride, J. M., Triplett-McBride, T., Davie, A., & Newton, R. U. (2002). The effect of heavy-vs. light-load jump squats on the development of strength, power, and speed. The Journal of Strength & Conditioning Research, 16(1), 75-82.
    Bone Mineral Density (and 15)
31. Pruitt, L. A., Taaffe, D. R., & Marcus, R. (1995). Effects of a one‐year high‐intensity versus low‐intensity resistance training program on bone mineral density in older women. Journal of Bone and Mineral Research, 10(11), 1788-1795.
32. Bemben, D. A., Fetters, N. L., Bemben, M. G., Nabavi, N. I. M. A., and Koh, E. T. (2000). Musculoskeletal responses to high-and low-intensity resistance training in early postmenopausal women. Med Sci Sports Exerc, 32(11), 1949-1957.
33. Kerr, D., Morton, A., Dick, I., & Prince, R. (1996). Exercise effects on bone mass in postmenopausal women are site‐specific and load‐dependent. Journal of bone and mineral research, 11(2), 218-225.
34. Taaffe, D. R., Pruitt, L., Pyka, G., Guido, D., & Marcus, R. (1996). Comparative effects of high‐and low‐intensity resistance training on thigh muscle strength, fiber area, and tissue composition in elderly women. Clinical Physiology, 16(4), 381-392.
    RPE (and 18 & 24)
35. Day, M. L., McGuigan, M. R., Brice, G., & Foster, C. (2004). Monitoring exercise intensity during resistance training using the session RPE scale. The Journal of Strength & Conditioning Research, 18(2), 353-358.
36. Alegre, L. M., Aguado, X., Rojas‐Martín, D., Martín‐García, M., Ara, I., and Csapo, R. (2015). Load‐controlled moderate and high‐intensity resistance training programs provoke similar strength gains in young women. Muscle & Nerve, 51(1), 92-101.
37. Fisher, J. P., & Steele, J. (2017). Heavier and lighter load resistance training to momentary failure produce similar increases in strength with differing degrees of discomfort. Muscle & Nerve, 56(4), 797-803.
    Body Composition (and 10, 15, 19, 20, & 22):
38. Vincent, K. R., Braith, R. W., Feldman, R. A., Magyari, P. M., Cutler, R. B., Persin, S. A., ... & Lowenthal, D. T. (2002). Resistance exercise and physical performance in adults aged 60 to 83. Journal of the American Geriatrics Society, 50(6), 1100-1107.
39. Schuenke, M. D., Herman, J. R., Gliders, R. M., Hagerman, F. C., Hikida, R. S., Rana, S. R., ... & Staron, R. S. (2012). Early-phase muscular adaptations in response to slow-speed versus traditional resistance-training regimens. European Journal of Applied Physiology, 112(10), 3585-3595.
40. Harris, G. R., STONE, M. H., O'BRYANT, H. S., PROULX, C. M., & JOHNSON, R. L. (2000). Short-term performance effects of high power, high force, or combined weight-training methods. The Journal of Strength & Conditioning Research, 14(1), 14-20.
41. Kraemer, W. J., Nindl, B. C., Ratamess, N. A., Gotshalk, L. A., Volek, J. S., Fleck, S. J., ... & Häkkinen, K. (2004). Changes in muscle hypertrophy in women with periodized resistance training. Medicine & Science in Sports & Exercise, 36(4), 697-708.
42. Fatouros, I. G., Tournis, S., Leontsini, D., Jamurtas, A. Z., Sxina, M., Thomakos, P., ... & Mitrakou, A. (2005). Leptin and adiponectin responses in overweight inactive elderly following resistance training and detraining are intensity related. The Journal of Clinical Endocrinology & Metabolism, 90(11), 5970-5977.
    Hypertrophy: Similar Improvement with Different Loads (and 1, 10, & 15)
43. Fink, J., Kikuchi, N., Yoshida, S., Terada, K., & Nakazato, K. (2016). Impact of high versus low fixed loads and non-linear training loads on muscle hypertrophy, strength and force development. Springerplus, 5(1), 1-8.
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45. Schoenfeld, B. J., Peterson, M. D., Ogborn, D., Contreras, B., & Sonmez, G. T. (2015). Effects of low-vs. high-load resistance training on muscle strength and hypertrophy in well-trained men. The Journal of Strength & Conditioning Research, 29(10), 2954-2963.
46. Chestnut, J. L., & Docherty, D. (1999). The effects of 4 and 10-repetition maximum weight-training protocols on neuromuscular adaptations in untrained men. The Journal of Strength & Conditioning Research, 13(4), 353-359.
    Hypertrophy: Trends Toward Differences and Differences Between Muscle Groups (and 11, 32, 34, 36, & 41)
47. Masuda, K., Choi, J. Y., Shimojo, H., & Katsuta, S. (1999). Maintenance of myoglobin concentration in human skeletal muscle after heavy resistance training. European journal of applied physiology and occupational physiology, 79, 347-352.
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    Hypertrophy: Differences in Hypertrophy with Different Loads (and 13, 23, 29, & 39)
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    Strength: Comparing Strength Following Light and Moderate Load Training (and 1, 10, 19, 23, 32, 44, 45, & 48)
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    Strength: Comparing Moderate and Heavy Loads (and 46, & 47)
55. Withers, R. T. (1970). Effect of varied weight-training loads on the strength of university freshmen. Research Quarterly. American Association for Health, Physical Education and Recreation, 41(1), 110-114.
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    Strength: Training Loads for Older and Adolescent Populations (and 31, 32, 34, 38, & 42)
62. De Vos, N. J., Singh, N. A., Ross, D. A., Stavrinos, T. M., Orr, R., & Fiatarone Singh, M. A. (2005). Optimal load for increasing muscle power during explosive resistance training in older adults. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences, 60(5), 638-647.
63. Fatouros, I. G., Kambas, A., Katrabasas, I., Leontsini, D., Chatzinikolaou, A., Jamurtas, A. Z., ... & Taxildaris, K. (2006). Resistance training and detraining effects on flexibility performance in the elderly are intensity-dependent. The Journal of Strength & Conditioning Research, 20(3), 634-642.
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65. Van Roie, E., Delecluse, C., Coudyzer, W., Boonen, S., & Bautmans, I. (2013). Strength training at high versus low external resistance in older adults: effects on muscle volume, muscle strength, and force–velocity characteristics. Experimental gerontology, 48(11), 1351-1361.
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68. Faigenbaum, A. D., Loud, R. L., O'CONNELL, J. I. L. L., Glover, S., O'CONNELL, J. A. S. O. N., & Westcott, W. L. (2001). Effects of different resistance training protocols on upper-body strength and endurance development in children. The Journal of Strength & Conditioning Research, 15 (4), 459 – 465.
    Strength: Comparing Extremities (and 12, 14, 33, 36, & 37)
69. Young, K., McDonagh, M. J. N., & Davies, C. T. M. (1985). The effects of two forms of isometric training on the mechanical properties of the triceps surae in man. Pflügers Archiv, 405, 384-388
70. Moss, B. M., Refsnes, P. E., Abildgaard, A., Nicolaysen, K., & Jensen, J. (1997). Effects of maximal effort strength training with different loads on dynamic strength, cross-sectional area, load-power and load-velocity relationships. European journal of applied physiology and occupational physiology, 75, 193-199.
    Strength: Comparing the Effects of Load and Tempo (and 20, 22, & 29)
71. Westcott, W. L., Winett, R. A., Anderson, E. S., & Wojcik, J. R. (2001). Effects of regular and slow speed resistance training on muscle strength. Journal of Sports Medicine and Physical Fitness, 41(2), 154.
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    Endurance (14, 22, 23, 38, 45, 47, 49, 53, 54, 62, 65, 67, 68). Power Single Session Power Output:
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74. Baker, D., Nance, S., & Moore, M. (2001). The load that maximizes the average mechanical power output during jump squats in power-trained athletes. The Journal of Strength & Conditioning Research, 15(1), 20-24.
75. Cronin, J. B., McNair, P. J., & Marshall, R. N. (2003). Force-velocity analysis of strength-training techniques and load: implications for training strategy and research. The Journal of Strength & Conditioning Research, 17(1), 148-155.
76. Kawamori, N., Crum, A. J., Blumert, P. A., Kulik, J. R., Childers, J. T., Wood, J. A., ... & Haff, G. G. 2005).Influence of different relative intensities on power output during the hang power clean: Identification of the optimal load. The Journal of Strength & Conditioning Research, 19(3), 698 – 708.
    Power: Outcomes from Training with Various Loads (and 22, 30, 40, 41, 51, & 70)
77. Kaneko, M., Fuchimoto, T., Toji, H., & Suei, K. (1983). Training effect of different loads on the force-velocity relationship and mechanical power output in human muscle. Scand J Sports Sci, 5, 50-55.
78. Berger, R. A. (1963). Effects of dynamic and static training on vertical jumping ability. Research Quarterly. American Association for Health, Physical Education and Recreation, 34(4), 419-424.