The training split you choose determines how you distribute your weekly training volume across sessions. It affects training frequency per muscle group, session length, recovery between sessions, and ultimately your results. Yet most lifters choose their split based on what their favorite influencer does, not on what the evidence actually supports for their situation.

Let us break down the three most popular splits — Push/Pull/Legs (PPL), Upper/Lower, and Full Body — with an honest look at the research, the practical trade-offs, and who each split is actually best for.

The Frequency Question

Before comparing splits, we need to address the elephant in the room: training frequency. Schoenfeld, Ogborn, and Krieger published a meta-analysis in 2016 that found training each muscle group at least twice per week produced significantly greater hypertrophy than once per week, even when total weekly volume was equated.

This finding has massive implications for split selection. Any split that results in hitting a muscle group only once per week is likely leaving gains on the table — unless total volume is very high in that single session (which creates its own problems with diminishing returns within a session and excessive muscle damage).

More recent research from Schoenfeld and colleagues (2019) investigated whether three or more sessions per week offered additional benefits over two. The results were less clear-cut: three times per week showed a slight, non-significant trend toward greater hypertrophy compared to two. The practical takeaway is that 2x per week per muscle group appears to be the minimum effective frequency, and going beyond 2-3x offers diminishing returns for most people.

Push/Pull/Legs (PPL)

PPL divides training into three workout types: push muscles (chest, shoulders, triceps), pull muscles (back, biceps, rear delts), and legs (quads, hamstrings, glutes, calves). You rotate through these three sessions across the week.

The critical caveat with PPL: If you train 3 days per week with a PPL split, each muscle group only gets hit once per week. This directly contradicts the frequency research. PPL only achieves the recommended 2x/week frequency if you train 6 days per week (PPL-PPL), which is a significant time commitment that many people cannot sustain.

Advantages of PPL:

Clean organization — related muscles are trained together, which makes exercise selection intuitive
Minimal overlap between sessions, meaning sore muscles from yesterday rarely limit today's performance
Allows very high volume per session for each muscle group, which can be useful for advanced lifters who need 16-20+ sets per week per muscle group
Each session can be focused and efficient since you are only hitting 2-3 muscle groups

Disadvantages of PPL:

Requires 6 sessions per week for optimal frequency — this is unrealistic for many people
At 3 days per week, each muscle is only trained once — suboptimal per the research
At 4 or 5 days per week, the rotation creates uneven frequency (e.g., push gets hit twice but legs only once in a given week)
The "pull" day can become extremely long if you program adequate volume for back, biceps, rear delts, and potentially hamstrings (since deadlifts are technically a pull)

Best for: Lifters who can commit to 6 training days per week and have intermediate-to-advanced training experience requiring high per-muscle-group volume.

Upper/Lower Split

Upper/Lower divides training into upper body days (chest, back, shoulders, arms) and lower body days (quads, hamstrings, glutes, calves). Typically run as 4 days per week — Upper, Lower, rest, Upper, Lower, rest, rest.

This is, in many ways, the Goldilocks split. It achieves 2x/week frequency for every muscle group with only 4 training days. That aligns perfectly with the frequency research while leaving 3 recovery days per week.

Advantages of Upper/Lower:

Achieves 2x/week frequency with only 4 training sessions — time-efficient and sustainable
Good balance of volume per session without sessions becoming excessively long
Flexible: easy to adjust to 3 days (Upper-Lower-Upper one week, Lower-Upper-Lower the next) or 5 days for more advanced lifters
Natural periodization: you can have a "heavy" upper day and a "light" or "pump" upper day, varying intensity and exercise selection across the two weekly sessions
Adequate recovery: 48-72 hours between sessions for the same muscle groups

Disadvantages of Upper/Lower:

Upper body days can be long. You have chest, back, shoulders, biceps, and triceps to cover. At 3-4 sets each across 5 muscle groups, that is 15-20 sets in a single session, potentially taking 75-90 minutes.
Lower body days can feel brutally fatiguing because heavy squats, Romanian deadlifts, and leg presses in a single session accumulate enormous systemic fatigue
Less specialization per muscle group compared to PPL — you have less time to dedicate to each area

Best for: The majority of lifters. Intermediates, people with 4 days available, and anyone who wants a research-supported split that does not require living at the gym. This is the most common split recommended by evidence-based coaches like Eric Helms, Jeff Nippard, and Greg Nuckols.

Full Body Training

Full body workouts train every major muscle group in each session, typically performed 3 days per week (e.g., Monday, Wednesday, Friday).

Full body training has experienced a renaissance in evidence-based fitness circles, and for good reason. It achieves 3x/week frequency for every muscle group with only 3 training days — the highest frequency-to-time ratio of any split.

Advantages of Full Body:

3x/week frequency with only 3 sessions — maximum frequency efficiency
Each session provides a full-body anabolic stimulus. Research suggests muscle protein synthesis (MPS) remains elevated for 24-48 hours post-training in trained individuals (MacDougall et al., 1995). More frequent stimulation means more total time in an elevated MPS state.
Flexible and forgiving: if you miss a session, every muscle group still got trained 2x that week
Excellent for beginners who need practice with fundamental movement patterns and can grow on low per-session volume
Lower per-session fatigue for any individual muscle group, which can improve quality of later sets

Disadvantages of Full Body:

Volume ceiling: with 3 sessions per week, you can only fit 3-5 sets per muscle group per session before sessions become excessively long. That caps you at 9-15 sets per week per muscle group — which may be insufficient for advanced lifters.
Exercise selection becomes constrained: you need compound movements that hit multiple groups efficiently (squats, bench, rows, overhead press) because there is no time for extensive isolation work
Fatigue management within sessions is challenging — doing heavy squats, then bench press, then rows in one session means later exercises are always performed in a more fatigued state
As you advance, you may find it hard to push adequate volume per muscle group without sessions exceeding 90 minutes

Best for: Beginners (first 6-12 months), lifters who can only train 3 days per week, and intermediates who respond well to higher frequency with moderate per-session volume. Also excellent for older lifters who benefit from distributing fatigue across the week.

What the Evidence Says About Direct Comparisons

A study by Schoenfeld, Ratamess, Peterson, et al. (2015) directly compared a total body routine vs. a split routine in trained men. Both groups performed the same total weekly volume and exercises — the only difference was distribution. The total body group trained 3x/week (all muscles each session), while the split group used a traditional bro split (each muscle 1x/week). The total body group showed significantly greater increases in biceps thickness and a trend toward greater gains in other measurements.

However, this study compared 3x/week vs. 1x/week, not 3x/week vs. 2x/week. When frequency is equated to at least 2x/week, the differences between splits largely disappear, and other factors — adherence, enjoyment, schedule compatibility — become more important than the specific split structure.

The practical conclusion from the literature: the best split is the one that gets you to a minimum of 2x/week per muscle group while fitting your schedule and preferences. Beyond that threshold, the specific split matters far less than consistent adherence, progressive overload, and adequate recovery.

Decision Framework

Here is a simplified decision process:

3 days available: Full Body is optimal. Upper/Lower can work as an alternating 3-day (U-L-U / L-U-L).
4 days available: Upper/Lower is the strongest choice. Full Body 4x/week also works well.
5 days available: Upper/Lower with a 5th specialty day, or a PPL variant with modified rotation.
6 days available: PPL-PPL is a strong option, provided you can recover from the training density.

Training experience also matters. Beginners benefit from the movement practice that full body provides. Intermediates typically thrive on Upper/Lower. Advanced lifters who need very high volumes per muscle group may need the specialization that PPL offers.

How Forssa Selects Your Split

When you tell Forssa how many days per week you can train, the app selects the optimal split based on the frequency research. Three days yields Full Body. Four days generates Upper/Lower. Five or six days produces a PPL or Arnold Split variant — always ensuring each muscle group is trained at least twice per week.

The app also considers your experience level and session duration constraints. If you are a beginner with 45-minute sessions, you get a streamlined full body program. If you are an advanced lifter with 4 days and 90-minute sessions, you get an Upper/Lower split with enough volume headroom for serious work.

The point is that split selection should not be arbitrary. It should follow from your available training days, your experience level, and the body of research on training frequency. Forssa automates this decision so you can focus on what actually matters: showing up and training hard.

PPL vs Upper/Lower vs Full Body: Choosing Your Split