האם יש חדש בנוגע לווליום כנגד תדירות?

[ran_z]

הנה הפוסט.

אין שום בעיה להקפיץ אותו אם יש לך שאלות נוספות בנושא.
אני באופן אישי הבעתי את הדעה שלי מס' פעמים בנושא ואין לי כוח לפתוח שוב את התיבת פנדורה הזאת ולהחיות את הוויכוח הזה.

[THE_JUGGERNAUT]

תעשה חיים:

Bumpage
Winett chimes in

***
Science Department

How Does the Training Load and Frequency of Training Impact Muscular Development?

Wernborn M, Augustsson J, Thomee R.

The influence of frequency, intensity, volume, and mode of training on whole muscle cross-sectional area in humans.

Sports Medicine.2007; 37: 225-264.

Wernborn and colleagues undertook an ambitious task. Their aim was to investigate through existing studies on resistance training how the training load and frequency of training affected muscular development as measured by increases in muscle cross-section areas (CSA).

Most prior reviews of resistance training have focused on strength and strength related outcomes. There are various recommendations and protocols based on the belief that training for strength and training for hypertrophy require different approaches. Resistance training ëcampsí promote their own special ëhypertrophy routinesí. Currently, there is little empirical support for this widely held and promoted belief and set of hypertrophy routines.

Wenborn et al. conducted a detailed search of studies conducted from 1970 through 2006 that included scanning technologies to assess CSA. There were only enough studies in the literature that adequately measured CSA for the quadriceps (44 studies) and for the biceps (elbow flexors; 16 studies). For each study, Werborn et al. were able to derive a CSA measure for the entire duration for the study as well as a rate measure.

A major caveat is that most of the studies involved
participants with no previous experience in resistance training. The rate of CSA change is greater for people who were previously inexperienced than for people training for two to three years. For people training for many years, the rate of change is very small or negligible. Despite this caveat about the generalizability of the findings to experienced trainees, a number of the findings and statements made in the narrative are of interest. However, there also are some points of contradiction in their narrative and conclusions.

For both the quadriceps and biceps, training those muscle groups two times per week produced a greater rate of CSA than training once per week. However, training those muscle groups three times per week did not produce a greater rate of CSA than training those muscle groups twice per week.

Training those muscle groups with less than 60% of a 1 RM (60% of the resistance that can be used for one maximum repetition) generally produced a lower rate of CSA than training at about 70% to 85% of 1 RM. Volume of exercise was based on total number of repetitions performed per muscle group in a session. This can be a confusing and meaningless way to measure volume because the number of repetitions performed with a given resistance is dependent upon the duration of the repetitions as well as a number of other factors such as how strictly repetitions were performed.

But, if the volume of work affects increases in CSA, what aspect of the volume of work is important? Wernborn et al. noted (p. 249) that: ìBased on the available evidence, we suggest that the time-tension integral is a more important parameter than the mechanical work output (force x distance).î

In other words, rather than the number of repetitions, the actual time under tension appears to be the more important stimulus for increasing CSA. If that is true, then performing repetitions with very short durations, or performing ëexplosiveí repetitions, may not be very effective motor recruitment strategies. Rapid movement and literally throwing a weight involves using a good deal of momentum and diminishes the time under tension.

Besides some issues with definitions and measurement, there are some other points of inconsistency in this empirically based review. Wernborn et al. noted a number of times that force, the amount of resistance, is a critical factor for increasing CSA. Yet, as noted above, their own data indicated that there was a wide range of force (percent of 1RM) that was effective for increasing CSA. The authors also indicated a number of times that the size principle of motor unit recruitment (see April, 2007) points to the use of high force to maximize motor unit recruitment. Then, in a number of other instances, Werborn et al. noted the importance of using near-maximal effort in training (p. 248) when using more moderate resistance and provided evidence of this point from one elegantly designed study.

In fact, earlier in the paper, Werborn indicated: ìAchieving recruitment of the greatest possible number of motor units in the target muscle(s) and making those motor units fire at high rates and for sufficient lengths of time are obvious prerequisites for inducing significant hypertrophy."

Still, it appears that maximal loads are not necessary to ensure these conditions are met providing that the training is performed with close to maximum effort in at least one of the sets.î (p.244). The key variable for maximizing motor unit recruitment seems to be the degree of effort and not force or volume.

Despite, their extensive empirical review, Werborn et al. concluded with training recommendations that are familiar and actually contradict some of their own earlier points.

For conventional training, they recommend training muscle groups two-three times per week (their own data indicated no differences in outcomes between two to three days per muscle group), using a resistance that is 75% to 80% of 1 RM (their own data indicated a wider range force and that effort is the key factor not load), and performing three to six sets per muscle groups (the prior quote suggested that it may be the near maximal effort in one set that is the most important stimulus for increasing CSA).

Bottom-line: At 40 pages, 11 figures (graphics with data), two large tables, and with 227 references, this is likely the most extensive review ever published of training variables affecting muscular hypertrophy. The data and long review seem to obscure very simple findings and training recommendations.

Consider even the issue of sets per muscle group. As has been often noted (see April, 2007), many exercises affect multiple muscle groups. Suppose performing three sets per muscle group using one set per exercise was optimal. An upper body routine can include one set of a chest press, a seated overhead press at 80 degrees, and dips or a similar movement. Given how exercises affect different muscle groups, then chest, deltoids, and triceps would have been trained with three sets.

You can see how this is true for other exercises and muscle groups. The findings then simply indicate that you should perform a routine with exercises that train muscle groups twice per week and you should have a high degree of effort at the end of all or most of your sets. Not much else seems to matter. Notice also that this simple approach would maximize both strength and muscular hypertrophy.