When it comes to strength training workouts, there can be infinite permutations and combinations in terms of splits, exercise sequences, number of reps & sets, rest between sets etc.
But when it comes to strength & hypertrophy-based training in the gym, there are primarily:
- Bro-Split workouts: this split involves training only one muscle in a workout, once per week. Each muscle is trained with much higher volume, as the entire workout is dedicated to that muscle. This split is mainly practiced by bodybuilders.
- Full-body workouts: in a full body workout, you train the entire body in one single day. Depending on the level of the person, it can be performed for 3, 4, 5, or 6 days/week.
- Upper-/lower-body split workouts: in this split, the upper body is trained on one day, and the lower body on the other. Depending on the level of the person, it can be performed as a 4 days/week or 6 days/week routine, with equal number of days for each upper & lower body.
- Push-Pull Legs workouts: these splits are similar to the Upper-Lower split. Again depending on the individual training experience, it is performed as a 3 days/week or 6 days/week schedule, with equal number of days to Push muscles (chest, triceps & shoulders), Pull muscles (back & biceps), and Legs.
- Muscle-group split workouts: these splits involve multiple variations in terms of body parts trained in a single session. Generally two muscles are trained together, and more can also be trained.
Bodybuilders, and generally those seeking a certain degree of hypertrophy, tend to use split workouts. Fitness enthusiasts, athletes and weightlifters prefer workouts which address the entire body, but may use different kind of split workouts too.
When it comes to bro-split, it is considered a bit inferior as compared to other splits. Remember, we are talking about 100% drug-free individuals here. Most of the hypertrophy response we see in advanced bodybuilders, practicing bro-splits is due to the effect of anabolic steroids.
A 2016 meta-analysis, determined the effects of resistance training frequency on hypertrophic outcomes. When comparing studies that investigated training muscle groups between 1 to 3 days per week on a volume-equated basis, the study indicated that frequencies of training twice a week promote superior hypertrophic outcomes to once a week. It can therefore be inferred that the major muscle groups should be trained at least twice a week to maximize muscle growth.
Other studies have also shown similar results. Which means, that bro-split, which focusses on training one muscle group once a week, would be inferior to split routines, in terms of development of strength & hypertrophy.
Does that mean, more is better ? No.
A study, compared the effects of 2 weekly-equalized volume and relative load interventions on body composition, strength, and power. 18 trained men were assigned to one of the following experimental groups: a low volume per session with a high frequency (LV-HF) group who trained for 4 days (Mondays, Tuesdays, Thursdays, and Fridays) or a high volume per session and low frequency (HV-LF) group who trained for 2 days (Mondays and Thursdays).
Although both training strategies improved performance and lower body muscle mass, only the HV-LF protocol increased upper body hypertrophy and improved body composition. This means, training each muscle 2 times a week is better for muscle growth than training 4 times a week.
However, another reason why Bro-splits are inferior to split routines, is because with higher frequency, you are able to perform higher number of quality sets. For e.g. in a Bro-split, if you are doing 4 exercises of a single body part, you would be fatigued after, first or second exercise itself. And the subsequent exercises won’t be getting their due.
On the other hand, if you do 2 exercises on one day, and the other 2 on the upcoming upper body day, you would be able to perform all the exercises with equal energy.
Now when the bro-splits are ruled out, comes the 2nd question, i.e. out of the remaining splits, which one is superior. Answer is none as such, as there are many factors to be considered, and most studies haven’t really shown any major difference in terms of strength, hypertrophy, or change in body composition.
For e.g. when it comes to untrained individuals, or beginners, recommendations are mixed.
- A study, investigated which of the two ways of structuring strength training workouts was more effective at improving strength levels, full-body workouts or split workouts; in 28 male university students, with no previous strength training experience.
After the completion of an 8-week intervention period, significant improvements in body fat percentage, levels of muscular strength on the upper body and on the lower body were observed in both, full body workout group & the split-body routine group. However, no significant differences between groups were found neither in the strength tests performed, nor body composition.
2. Another study, compared the effects of different resistance training programs on measures of muscle strength and hypertrophy. Sixty-seven untrained subjects were randomized to one of two groups: Split Workout Routine, in which muscle groups were trained twice per week, or Full-Body Workout Routine, in which muscle groups were trained four times per week. Both groups performed eight to 12 repetition maximum per set, with 60 seconds of rest between sets.
Changes in 1RM – Bench Press (18.1% and 17.5% for Split Workout Routine and Full-Body Workout Routine Group, respectively) and 1RM – Squat (28.2% and 28.6% for Split Workout Routine and Full-Body Workout Routine Group, respectively) were almost identical. Effect sizes for 1RM – Bench Press and 1RM – Squat, were also very similar between groups.
Individuals in the Split Workout Routine and the Full-Body Workout Routine Groups experienced similar maximal strength gains from baseline to postintervention. Thus, resistance training twice or four times per week has similar effects on neuromuscular adaptation, provided weekly set volume is equal.
3. A study, assessed the efficacy of a 12-week upper/lower split- versus a full-body resistance training program on maximal strength, muscle mass and explosive characteristics.
Fifty resistance untrained women were matched according to baseline strength and randomized to either a full-body (FB) routine that trained all of the major muscle groups in one session twice per week, or a split-body program (SPLIT) that performed 4 weekly sessions (2 upper body and 2 lower body). Both groups performed the same exercises and weekly number of sets and repetitions. Each exercise was performed with three sets and 8–12 repetition maximum (RM) loading.
This study did not show any benefits for split-body resistance-training program compared to full-body resistance training program on measures of maximal- and explosive muscle strength, and muscle mass.
4. However, another study, investigated the effect of volume-matched strength training programs with different frequency, during a period of 11 weeks, in untrained subjects. They performed, knee-extension exercise at 67% of their estimated one-repetition maximum either one session per week or three sessions per week.
After 11 weeks of training, the study found that, training each muscle 3 times/week as you do in a full body split, is not only more effective at improving strength in untrained individuals when compared to lower training frequencies.
Therefore, when it comes to beginners, both full body & split routines are beneficial for them, where each muscle group should be trained 2-3 times.
When it comes to intermediate/advanced lifters, there is no one single recommendation, as many factors come into play.
- A study, compare the effects of total body (TB) versus split routine (SR) resistance training workouts on maximal strength and muscle hypertrophy in 21 trained men. Both groups performed a 10-week resistance training program, with same training volume.
This study demonstrated that both total-body and Split-routine 10-week training programs can significantly increase maximal strength and muscle mass gains in experienced, resistance-trained men.
However, a Total-body approach may be optimal to stimulate maximal strength adaptations in highly trained men. The use of an Split-routine training program, however, may be more conducive in stimulating muscle growth by concentrating the training volume for each muscle group in a single workout.
“Strength and conditioning coaches should be aware that different strategies may be adopted during different phases of a periodized strength training program to better stimulate either maximal strength or muscle hypertrophy development. In particular, Split-routine may be more appropriate during a hypertrophy phase of a periodization program, while Total-body approach may be suitable for the maximum strength phase”, said the researchers.
2. Another study, compare the effects of equal-volume resistance training (RT) performed with different training frequencies on muscle size and strength. Sixteen men with at least one year of resistance training experience were divided into two groups, that trained each muscle group once and twice a week, respectively, for 10 weeks.
The study suggested that there were no differences in the results promoted by equal-volume resistance training performed once or twice a week on upper body muscle strength in trained men. With either once or twice a week training, adaptations appear largely minimal in previously trained males.
3. A study, examined the effects of resistance training frequency performed 3 times per week vs. resistance training performed 6 times per week, under volume-equated conditions in resistance-trained men.
Researchers found that, when training volume is equated, it seems that Resistance training performed either 3 or 6 times per week can result in similar strength gains, hypertrophy gains, and increase in muscle endurance, over a 6-week training period.
4. A study, compared changes in muscle strength and hypertrophy between volume-equated resistance training (RT) performed 2 versus 3 times per week in trained men. Thirty-six resistance-trained men were assigned to one of the two groups: a split-body training routine (SPLIT) with muscle groups trained twice per week over four weekly sessions, or a total-body routine (TOTAL), with muscle groups being trained three times per week over three weekly sessions; for a total of 10 weeks.
The study concluded that, a training frequency of 2 versus 3 days per week produces similar increases in muscular adaptations in trained men over a 10-week training period. Nonetheless, effect size differences favoured SPLIT for all hypertrophy measures, indicating a potential benefit for training two versus three days a week when the goal is to maximize gains in muscle mass.
5. Another meta-analysis study, compared muscular strength outcomes with different RT frequencies. The study, suggested a significant effect of RT frequency as higher training frequencies are translated into greater muscular strength gains. However, these effects seem to be primarily driven by training volume because when the volume is equated, there was no significant effect of RT frequency on muscular strength gains.
Thus, from a practical standpoint, greater training frequencies can be used for additional RT volume, which is then likely to result in greater muscular strength gains. However, it remains unclear whether RT frequency on its own has significant effects on strength gain. It seems that higher RT frequencies result in greater gains in muscular strength on multi-joint exercises in the upper body and in women, and, finally, in contrast to older adults, young individuals seem to respond more positively to greater RT frequencies.