Partial Reps to Failure: Can They Build the Same Muscle With Fewer Sets?

Key Takeaways: Partial Reps to Failure

• Training past full-range failure with short partial reps in the stretched position led to about the same calf muscle growth as traditional full-range training, even though it used only half as many sets.
• In this study, both approaches increased calf size by about eight percent over ten weeks.
• The big practical lesson is simple: if your goal is muscle growth and you want a more time-efficient workout, extending a set with partial reps may help you get similar results with less total set volume.

Why Partial Reps to Failure Matter

Every lifter has asked some version of the same question: do I really need this many sets to grow? That is exactly why partial reps to failure have become such an interesting topic for lifters who want more growth from less work.

That is exactly why this new study matters. In “Does Performing Partial Repetitions Beyond Momentary Failure Enhance Muscle Hypertrophy in Volume-Load-Equated Calf-Raise Resistance Training?” by Amirali Goli, Parsa Attarieh, João Pedro Nunes, Saman Nehegadar, Saaed Khani, Mohmad Fashi, and Sajjad Ahmadizad, published in the International Journal of Exercise Science in 2026, the researchers tested a very practical idea: what happens if you take a normal set to failure, then keep going with short partial reps in the stretched part of the movement?

That question matters because extending a set with partial reps in the stretched position may let you build the same amount of muscle with fewer sets. In other words, partial reps to failure may offer a more efficient way to train, especially when paired with stretched position training. For busy lifters, that is not a small detail. It could mean shorter workouts, less session fatigue, and a smarter way to train stubborn muscles like calves.

The study focused on standing calf raises in untrained young men. It also gives us a useful real-world look at full range vs partial reps, since one condition used standard full-range training while the other used partial reps to failure after the full reps were done. One leg was trained with traditional full-range sets to failure. The other leg was trained with fewer sets, but each of those sets continued with partial reps after full-range failure. In plain English, the researchers wanted to know whether doing more work inside each set could replace doing more sets overall.

The answer was interesting. The men grew about the same amount of calf muscle either way, but the partial-rep method got there with fewer sets. That does not mean more is always better. It means efficiency may matter more than many people think.

Partial Reps to Failure, Lengthened Partials, and Stretched Position Training

This study did not appear out of nowhere. It builds on a growing body of work on partial reps to failure, lengthened partials, and stretched position training. It builds on a growing body of research suggesting that the stretched part of a lift may be especially useful for muscle growth.

One of the most important earlier calf studies came from Kassiano and colleagues. Their work helped push the conversation around lengthened partials and stretched position training into the mainstream. In that study, young women trained calves using either a full range of motion or a shorter range done in the stretched part of the movement. The stretched-position partial reps led to greater growth in the calf muscle than the full-range approach.¹ That finding made the full range vs partial reps debate much more interesting, because it suggested that the part of the movement you train may matter as much as the rep itself. That finding helped push the idea that where you load the muscle may matter just as much as how many reps you do.

The paper by Goli and colleagues also discussed an earlier calf study by Larsen and colleagues. That earlier work is also relevant to the current discussion around partial reps to failure. In that work, full-range reps followed by partial reps beyond failure produced more calf growth than stopping at normal failure. However, there was a catch: the beyond-failure condition also did much more total work. That left an open question. Did the extra growth happen because partial reps are special, or simply because the lifters did more work? The new paper tried to answer that exact question by matching total work more closely between conditions.²

There is also broader support for the idea that getting close to failure matters for growth. That is one reason partial reps to failure and lengthened partials keep getting attention. A large meta-regression by Robinson and colleagues found that muscle growth tends to improve when sets are taken closer to failure, even though strength does not seem to depend on failure in the same way. In other words, hard sets appear to matter, especially when the goal is muscle size.³

At the same time, not every study shows a clear win for partial reps over full-range lifting. The full range vs partial reps question is more nuanced than social media often makes it sound. For example, Wolf and colleagues found that lengthened partial reps and full-range training produced similar muscle gains in trained lifters when the rest of the program was kept the same. That is an important reminder that partials are probably not magic. They are a tool, and like most tools, they seem to work best in the right context.⁴

Put all of that together, and the literature points in a pretty sensible direction. Partial reps to failure, lengthened partials, and stretched position training seem most useful when they help turn a hard set into a more productive set rather than simply adding junk fatigue. Training close to failure works. Loading the stretched part of a movement may offer an extra advantage. And partial reps may be most useful when they help you turn one hard set into a more productive set.

Partial Reps to Failure vs Full Range vs Partial Reps

Now to the new study itself, which gives us one of the clearest direct tests of partial reps to failure in calf training.

The researchers recruited sixteen untrained young men. Their average age was twenty-five years, and their average body mass was 75.2 kilograms, or 165.8 pounds. The study lasted ten weeks, with calf training performed twice per week. Each participant trained both legs, but each leg followed a different method.

One leg used traditional full-range calf raises to failure. During the first six weeks, that leg performed four sets per session. During the final four weeks, it performed six sets per session. Across the full study, that added up to ninety-six total sets.

The other leg used a different plan. It first performed full-range calf raises to failure, then continued with short partial reps in the stretched part of the movement until it could not keep going. During the first six weeks, that leg performed two sets per session. During the final four weeks, it performed three sets per session. Across the study, that added up to forty-eight total sets.

So yes, the partial-rep condition used half the number of sets. That makes this a very practical full range vs partial reps comparison, not just a theory piece.

Despite that, both conditions produced almost the same increase in calf muscle thickness. That is why this paper matters so much in the full range vs partial reps conversation. The average increase was about eight percent in both conditions. The inside calf muscle and the outside calf muscle both grew in a similar way across the two approaches. The researchers also matched total training work closely enough that neither condition had a clear advantage there.

Where things got more interesting was the per-set analysis. This is where partial reps to failure and lengthened partials really stood out. When the researchers looked at how much muscle growth each set seemed to produce, the partial-rep condition came out ahead. Put simply, each set did more.

That is the real headline. Not more total growth. Not a miracle result. Just better efficiency.

Why Partial Reps to Failure and Lengthened Partials May Work

This is where the study becomes useful for real training.

A lot of people hear about advanced methods like drop sets, rest-pause, or partial reps and assume they must be better because they feel harder. The real value of partial reps to failure is not that they feel brutal. It is that they may create more useful work inside each set. That is not always true. Sometimes they are just more tiring. What makes this paper valuable is that it separates the feeling of effort from the result.

When total work was matched, taking a set to full-range failure and then adding partial reps did not produce clearly greater calf growth than traditional full-range training to failure. That matters because it keeps us honest. The method did not outperform regular training in absolute results.

But there is another way to look at it, and this is the more practical one.

The partial-rep method reached the same growth with fewer sets. That is the strongest practical argument for partial reps to failure in this study. That means a lifter might be able to save time, reduce total set count, and still get a strong growth signal. For anyone who struggles to fit long workouts into a busy week, that is a very compelling trade.

Why might this happen?

The most likely reason is that the partial reps kept the muscle working in the stretched portion of the exercise, where the calf may experience high tension. That fits well with the broader ideas behind stretched position training and why lengthened partials may work. In plain language, the muscle keeps working hard in the part of the lift that may be especially useful for growth. The study authors also noted that the stretched position may increase the force placed on the working calf muscles, which could help explain why each set was more productive.

This does not mean every exercise should suddenly become a marathon set of ugly partial reps. The lesson is not to turn every workout into chaos. It is to use partial reps to failure in a controlled way when the setup allows it. That would be a mistake. The point is not to turn training sloppy. The point is to use controlled partial reps after good full-range reps when the exercise is safe and stable enough to allow it.

That is also where calves make sense. Calf raises are relatively simple. They are easy to control. And they are a muscle group many lifters find frustrating to grow. A method that makes each set count more has obvious appeal here.

There are still limits to what this study can tell us. The participants were untrained young men, so we cannot assume the exact same result in advanced bodybuilders. The study focused on calves, not on every muscle group. And while the results were clear on efficiency, they do not prove that partial reps beyond failure are always the best option.

Still, the message is strong: if you can safely extend a set in the stretched position, you may not need as many sets to get the job done. That is the best case for stretched position training in this context.

Practical Applications: Using Partial Reps to Failure in Real Training

So what should a lifter actually do with this when thinking about partial reps to failure?

First, do not throw out full-range training. Full-range reps still worked very well in this study. They built muscle. They remain a solid base for most programs.

Second, partial reps become interesting when time is limited or when you want to get more out of fewer sets. That is where partial reps to failure, lengthened partials, and stretched position training become especially useful. A smart way to apply this is on stable exercises where technique is easy to control. Calf raises are the clearest example. Leg extensions and some arm exercises may also fit that idea, but the best evidence in this article is for calf training.

Third, keep the partial reps controlled. In any full range vs partial reps setup, execution matters. In this study, the lifters first did full-range reps until they could no longer reach the top position. Then they continued with short reps in the lower, stretched part of the movement until they could no longer complete that shorter motion. That is very different from bouncing, rushing, or using sloppy technique.

A simple practical setup would look like this:

Start with a full set of standing calf raises using a weight you can lift for about ten to fourteen hard reps. Once you can no longer complete another clean full rep, continue with short controlled reps in the bottom stretched portion. Stop when you can no longer do those partial reps with control.

That approach will likely make each set feel brutal, so you probably will not need many sets. In fact, that is the whole point.For bodybuilders and physique-focused lifters, this idea is especially appealing for smaller muscle groups or for accessory work near the end of a session. Partial reps to failure can be a smart tool when you want a high-effort finish without adding a lot of extra sets. Instead of piling on extra sets, you may be better off making one or two sets count more.

And honestly, that is one of the most useful lessons in hypertrophy training. More work is not always better. Better work is better.

References

1               Kassiano, W. et al. Greater Gastrocnemius Muscle Hypertrophy After Partial Range of Motion Training Performed at Long Muscle Lengths. J Strength Cond Res 37, 1746-1753 (2023). https://doi.org/10.1519/jsc.0000000000004460

2               Goli, A. et al. Does Performing Partial Repetitions Beyond Momentary Failure Enhance Muscle Hypertrophy in Volume-Load-Equated Calf-Raise Resistance Training. International Journal of Exercise Science (2026). https://doi.org/10.70252/IJES2026403

3               Robinson, Z. P. et al. Exploring the Dose-Response Relationship Between Estimated Resistance Training Proximity to Failure, Strength Gain, and Muscle Hypertrophy: A Series of Meta-Regressions. Sports Med 54, 2209-2231 (2024). https://doi.org/10.1007/s40279-024-02069-2

4               Wolf, M. et al. Lengthened partial repetitions elicit similar muscular adaptations as full range of motion repetitions during resistance training in trained individuals. PeerJ 13, e18904 (2025). https://doi.org/10.7717/peerj.18904