Hypertrophy Research - Training Frequency
Written by Daniel Moore and Ron Sowers
Wednesday, 26 October 2005
Training Frequency
Training frequency is a much debated and apparently, variable part of training. Multiple aspects of recovery and adaptation are blended together, such as rest, sleep, mental state, nutrition, age, and immune function. Prescribing a fixed and/or perfect frequency is thus very difficult. What is usually needed is a conditional prescription. i.e. If a person pays close attention to all controllable factors, rest, sleep, diet, etc. a general recommendation can be made.
Another point of consideration is optimal vs. workable. It's obvious that more equally productive sessions per time period will result in faster progress. Adjustments in the program may also be considered as a variable. A trainee may choose to alter the intensity and/or duration of training sessions while keeping a fixed frequency, or, they may adjust frequency while keeping a fixed intensity and/or duration. Both sides have 'logical' reasoning for each action. What is superior has not been proven.
What science has to say
Busso (1) compared training frequencies of 3d vs 5d per week. The conclusions were that 5d per week led to a higher level of fatigue and thus a longer recovery time. Obviously, the subjects were not recovering between sessions. If one is training in a 'single factor' model, the goal is to replicate a 'stimulation -> rest -> recover -> adapt' scenario before a subsequent stimulation is induced.
DeMichele (2) Tested rotational torso strength gains between 1d, 2d, and 3d per week subjects. No difference between 2d or 3d per week were found, but both 2d and 3d were superior to 1d per week.
Carroll (3) tested strength and MHC gains in the leg muscles for 2d vs. 3d per week training. In this study, results were similar but higher strength gains were seen in the 2d per week subjects. Other work (4) by some of the same researches earlier had shown that 3X week training for 12 weeks increased increased arm girth (5%) and forearm extensor strength (39%), associated with the triceps brachii muscle.
Significant changes in hypertrophy have been seen using various training frequencies. Abe (6) used a 3X weekly protocol, Staron (5,7) used 2X weekly both training programs produced significant increases in mass. Hakkinen (8) also used a 3X weekly approach but divided the daily volume into two daily sessions. No systematic changes took place in the cross-sectional area (CSA) of the quadriceps femoris muscle or in maximal voluntary isometric strength of the leg extensor muscles over training period I with one daily sessions. However, a significant (p < 0.05) enlargement in the cross-sectional area of the muscle occurred during period II. Both phases where 3 weeks in length and this could account for not seeing changes in the initial phase simply too short of a duration to see any change but we will discuss this in our “Duration” section.
Looking at exercise frequency in older adults, Taafe(9) shows that training more frequently than one time per week had little impact compared to higher frequencies (2 or 3 times per week). Using three sets of eight exercises targeting major muscle groups of the upper and lower body, at 80% of one-repetition maximum (1-RM) for eight repetitions, muscle strength and lean body mass increased in the exercise groups relative to control, with no difference among frequency groups at any measurement interval.
Too much, too little too late?
One last consideration is recognizing over training. There are two ways the term 'over training' appears to be used.
Training more often than optimal, with no ill effect
Training more often than optimal, with ill effects (over training syndrome)
The latter is usually seen in high caliber athletes, and over a longer period of training time. The common ground being, the former will or could lead to the latter. Many researchers are looking at the over training syndrome and some new light is being shed on it. Smith (10) puts forth a hypothesis that over training compromises immune function, leading to a signaling of the CNS. This signaling generally leaves one feeling lack luster, depressed, or other feelings of malaise.
The 'take home' message
If one is willing, and/or able, to adjust the factors needed for proper recovery, and are a healthy adult, twice weekly training per muscle or muscle group appears to be the optimal prescription. Superior results have not been found for higher frequencies of stimulation (in longer term situations), but lesser results have been found for lower frequencies.
A chain is only as strong as it's weakest link, and results are the final proof of a program. Intelligent trainees will note progress, and adjust factors such as sleep, nutrition, and the like, so that recovery and adaptation may take place at the fastest pace. If a factor is unalterable, and progress cannot be made with an optimal frequency, the trainee must then, decide to either adjust the amount of work or the training frequency (11-13).
Daniel Moore and Ron Sowers
www.hypertrophy-research.com
(1.)Busso, T. Effects of training frequency on the dynamics of performance response to a single training bout. J Appl Physiol. 2002 Feb;92(2):572-80.
(2.)DeMichele, PL.Isometric torso rotation strength: effect of training frequency on its development.Arch Phys Med Rehabil. 1997 Jan;78(1):64-9.
(3.)Carroll, TJ. Resistance training frequency: strength and myosin heavy chain responses to two and three bouts per week.Eur J Appl Physiol Occup Physiol. 1998 Aug;78(3):270-5.
(4.)Jurimae, J. Changes in the myosin heavy chain isoform profile of the triceps brachii muscle following 12 weeks of resistance training.Eur J Appl Physiol Occup Physiol. 1996;74(3):287-92.
(5.)STARON, R. S., Skeletalmuscle adaptations during early phase of heavy-resistance training in men and women. J. Appl. Physiol. 76:1247–1255, 1994.
(6.) ABE, T. Whole body muscle hypertrophy from resistance training: distribution and total mass Br J Sports Med 2003;37:543-545
(7.)STARON, R. S. Muscle hypertrophy and fast fiber type conversions in heavy resistance-trained women. Eur.J. Appl. Physiol. 60:71–79, 1989.
(8.) H¨AKKINEN, K. Distribution of strength training volume into one or two daily sessions and neuromuscular adaptations in female athletes. Electromyogr. Clin. Neurophysiol.34:117–124, 1994.
(9.)Taafe, D. Once-weekly resistance exercise improves muscle strength and neuromuscular performance in older adults.J Am Geriatr Soc. 1999 Oct;47(10):1208-14.
(10.)SMITH, L. L. Cytokine hypothesis of overtraining: a physiological adaptation to excessive stress? Med. Sci. Sports Exerc., Vol. 32, No. 2, pp. 317-331, 2000
(11.)Cronin, J. Training volume and strength and power development. J Sci Med Sport. 2004 Jun;7(2):144-55.
(12.) American College of Sports Medicine position stand. Progression models in resistance training for healthy adults. Med Sci Sports Exerc. 2002 Feb;34(2):364-80. Review.
(13.)Halson, SL. Does overtraining exist? An analysis of overreaching and overtraining research. Sports Med. 2004;34(14):967-81. Review.