If you’ve spent any time searching for the “perfect” workout routine, you know how easy it is to drown in conflicting advice. What does the actual research say?

Researcher Menno Henselmans recently broke down three recent studies that challenge conventional wisdom on training splits, leg day, and protein intake. Here’s how you can use this data to train smarter and build more muscle.

1. Stop Obsessing Over Your Training Split

Many lifters swear by Push-Pull-Legs or Upper-Lower routines. But does the specific split you choose actually matter?

A recent study compared traditional push-pull workouts against a more fragmented upper-body split where isolation exercises were moved to different days. After 8 weeks, the results were clear: there were no significant differences in muscle growth for the biceps, triceps, or pecs, nor in bench press strength.

If you’ve been going back and forth between splits, our guide to choosing a workout split covers the key factors that actually matter.

The Takeaway: Your muscles respond to mechanical tension, not a particular routine name. The total training volume—weight multiplied by reps multiplied by sets—is the primary driver of growth. Research shows that as long as total weekly volume is matched, different splits produce virtually identical results.

• Focus on total tonnage. Choose the split that lets you accumulate the most high-quality volume per week. If spreading your work across more sessions helps you stay less fatigued and lift heavier, a full-body or high-frequency approach may be more efficient than a traditional bro split.
• Track it. SetsApart’s Volume Per Muscle Group feature automatically tallies your weekly tonnage for every muscle group—regardless of which split you’re running. You can see at a glance whether your chest got 14 hard sets this week or only 7 and adjust accordingly.

For a deeper look at why total volume matters more than any single programming variable, check out our articles on progressive overload and the minimum effective dose for muscle growth.

2. The Leg Day Question: Squats vs. Leg Extensions

We’ve all heard that “squats are king,” but are they enough to build a complete set of quads?

Research comparing Smith machine squats to leg extensions found that these two movements are complementary, not interchangeable. Each targets different parts of the quadriceps in ways the other cannot fully replicate.

What the Data Shows

• Leg Extensions were significantly better for growing the rectus femoris—the quad muscle that runs down the middle of the thigh. Squats often fail to load this muscle effectively because the rectus femoris crosses both the hip and knee joints, limiting its ability to produce force during a squat.
• Squats were superior for developing the vastus lateralis (the outer “quad sweep”) and building raw movement-specific strength.

The Takeaway: If you want complete quad development, you need both. Use squats for heavy compound loading and leg extensions to fill in the gaps.

Log both compound and isolation movements in SetsApart to track your hard sets across all quad exercises. This makes it easy to ensure you’re giving each muscle head enough stimulus—not just defaulting to squats and hoping for the best.

3. Does Extra Protein Improve Recovery and Performance?

High-protein diets get a lot of attention for their thermic effect—the energy your body spends digesting and absorbing protein. While this is real, its impact on lifters who are already hitting adequate protein targets may be smaller than you think.

A meta-analysis of 28 studies found that while protein has a high thermic effect in acute (short-term) measurements, this advantage often disappears in longer-term studies. For experienced lifters who already consume sufficient protein for muscle repair and growth, increasing intake further for a metabolic edge yields diminishing returns.

What This Means for Your Training

Research shows the marginal thermic benefit of extra protein amounts to roughly 50 additional calories burned—at the cost of consuming several hundred extra calories to get there. For recovery and performance, the practical takeaway is straightforward:

• Hit your protein target for muscle growth and recovery (typically 1.6-2.2 g/kg of body weight). This is the range supported by the bulk of the hypertrophy literature.
• Don’t rely on extra protein as a fat-loss strategy. Once recovery needs are met, additional protein offers negligible metabolic advantage.
• Prioritize training quality instead. The time and mental energy spent optimizing protein beyond adequate levels is better spent on training efficiency—managing rest periods, improving technique, and progressively overloading your lifts.

Putting It All Together

These three findings point toward the same principle: focus on the fundamentals that actually drive muscle growth rather than chasing marginal optimizations.

1. Prioritize volume over split selection. Don’t agonize over Push-Pull-Legs vs. Upper-Lower. Track your total weekly hard sets per muscle group and make sure the number is going up over time.
2. Mix your tools. Combine heavy compound movements with targeted isolation work for complete muscle development.
3. Optimize protein, then move on. Hit your daily target for recovery and growth, and redirect your attention to what happens in the gym.

SetsApart’s Volume Per Muscle Group feature ties all of this together. It tracks your hard sets and weekly tonnage automatically, so you can stop guessing and start making decisions based on your actual data—regardless of which split or exercises you choose.

Train hard, track what matters, and let the research guide your decisions.

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Source

This article was inspired by and summarizes key insights from the following video. Check out the video for more detail and subscribe to the channel—it’s a great resource for evidence-based training.

Watch the full video: 3 Sweet new studies to maximize your gains