Heavy and Light Training Days Attenuates Decline in Force Output During 3-Weeks High-Volume Resistance Training Kevin M. Carroll1, Jake R. Bernards1, James L. Miller1, Kimitake Sato1, Brad H. DeWeese1, and Michael H. Stone1 1Center of Excellence for Sport Science and Coach Education, Department of Sport, Exercise, Recreation, and Kinesiology, East Tennessee State University, Johnson City, TN Abstract Methods High volume resistance training is employed by coaches during training emphasizing enhanced body composition, hypertrophy, and work capacity. However, high volume training may cause levels of fatigue that impact strength and power performances. It is not well known if using fatigue- management strategies such as heavy and light days affect these performances. PURPOSE: To compare changes in kinetic variables following high volume resistance training employing heavy and light days. METHODS: Eight strength trained males (age = 27.4 + 4.2 years, body mass = 90.8 + 11.8 kg, isometric peak force = 4397.1 + 636.9) participated in the study. Pre-and post-training each subject was evaluated for isometric peak force (IPF), allometrically-scaled isometric peak force (IPFa), and rate of force development at 90 ms (RFD90) during an isometric mid-thigh pull test on a dual force platform sampling at 1000Hz. The training protocol consisted of resistance training 3 days/wk with each week progressing in intensity. Each 3rd training day was a light day (10% lighter than day 1). Paired-samples t-tests were calculated pre-post the 3 weeks to assess changes associated with training. Magnitudes of change were examined using percent change and effect size using Cohen’s d. RESULTS: The change in body mass (BM) was significantly higher (90.8 + 11.8 kg to 92.5 + 11.7 kg) (p = 0.03) while no statistical differences were observed in IPF (4397.1 + 636.9 N to 4380.4 + 432.9 N), IPFa (218.0 + 25.5 N/kg0.67 to 215.5 + 23.2 N/kg0.67), or RFD90 (10155.6 + 5511.3 N·s-1 to 9208.3 + 4547.3 N·s-1) (p > 0.05). Percent change for BM, IPF, IPFa, and RFD90 were as follows: 1.9%, -0.4%, -1.2%, -9.3%, respectively. Effect sizes for BM (d = 0.15), IPF (d = 0.03), IPFa (d = 0.10), and RFD90 (d = 0.19) indicated trivial effects pre-post high volume training. CONCLUSIONS: High volume resistance training is often concomitant with reductions in strength or RFD performance. The results of the study indicate that force outputs were spared following 3-wks high volume training when employing heavy and light days. Although not significant, a reduction in RFD90 of 9.3% is practically significant for athletes. It seems that while strength variables were largely unaffected, explosiveness (i.e. RFD90) may be more sensitive to high training volumes regardless the fatigue management strategies used. Table 1. Resistance Training Program   Week (sets)x(reps) Day 1 and 2 Day 3 (pre) Isometric Mid-Thigh Pull Testing 1 3x10 80.0% 70.0% 2 85.0% 75.0% 3 90.0% (post) Isometric Mid-Thigh Pull Testing Table 2. Training Exercises Day 1 Day 2 Day 3 Back Squat, Overhead Press, Bench Press, Dumbbell Triceps Extension Mid-thigh pull, Stiff-Legged Deadlift, Bent-Over Row, Bent Lateral Raise Figure 1. Average daily Volume Load (load x repetitions) throughout a 3-week block of 3x10. Average weekly intensities increased throughout the 3-weeks (80% - 85% - 90% of best 3x10). Day 1 was considered the ‘heavy’ day and consisted of pushing exercises (e.g. back squat, overhead press, etc.). Day 2 matched the intensity of Day 1 but included pulling exercises (e.g. mid-thigh pull, stiff-legged deadlift, etc.). Day 3 was considered the ‘light’ day- which included the exact same exercises as Day 1 but reduced intensity of 10%. Figure 2. The set-position of the isometric mid-thigh pull testing. The knee angle was set as 130 + 5° and the hip angle as 150 + 5°. Each subject was instructed to pull “as fast and as hard” as they could for each trial. The average of 2 trials were used for statistical analysis. Results Conclusions Our results indicated three-weeks of high volume training using heavy-and-light days resulted in no significant declines in either maximal isometric force production or rate of force development. The significant increase in body mass over the training period could indicate greater muscle cross-sectional area, possibly contributed to the maintenance of force production. While the 9.3% reduction in RFD 90ms was not significant, this amount of decline could be significant for athletes in competitive phases. Heavy-and-light day utilization during high volume training phases could help attenuate the decline in force and rate of force, possibly due to reduction in accumulated fatigue. However, the reduction in RFD 90ms suggests that high volume training should still remain in general preparatory, out-of-season training. References Figure 3. Change in isometric peak force (IPF), allometrically scaled peak force (IPFa), and rate of force development from 0-90ms (RFD 90ms) from three-weeks of high volume training using heavy-and-light days. While IPF and IPFa remained relatively unchanged following the training phase (-0.4% and -1.4%, respectively), RFD 90ms decreased by 9.3%. None of these changes were significant (p > 0.05). Additionally, body mass significantly increased (p=0.03). 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), 698. doi:10.1186/s40064-016-2333-z Haff, G. G., Jackson, J. R., Kawamori, N., Carlock, J. M., Hartman, M. J., Kilgore, J. L., . . . Stone, M. H. (2008). Force-time curve characteristics and hormonal alterations during an eleven-week training period in elite women weightlifters. Journal of strength and conditioning research, 22(2), 433-446. doi:10.1519/JSC.0b013e31816191be Hopkins, W. G. (2002). A Scale of Magnitudes for Effect Statistics. Retrieved from http://www.sportsci.org/resource/stats/index.html Hornsby, W., Haff, G., Sands, W., Ramsey, M., Beckham, G., Stone, M., & Stone, M. (2013). Alterations in strength characteristics for isometric and dynamic mid-thigh pulls in collegiate throwers across 11 weeks of training. Gazzetta Medica Italiana, 172(12), 929-940. Kraska, J. M., Ramsey, M. W., Haff, G. G., Fethke, N., Sands, W. A., Stone, M. E., & Stone, M. H. (2009). Relationship Between Strength Characteristics and Unweighted and Weighted Vertical Jump Height. International Journal of Sports Physiology and Performance, 4(4), 461-473. Painter, K. B., Haff, G. G., Ramsey, M. W., McBride, J., Triplett, T., Sands, W. A., . . . Stone, M. H. (2012). Strength Gains: Block Versus Daily Undulating Periodization Weight Training Among Track and Field Athletes. International Journal of Sports Physiology and Performance, 7(2), 161-169. Stone, M. H., Stone, M. E., & Sands, W. A. (2007). Principles and practice of resistance training. Champagne, IL: Human Kinetics.