# Creatine, Cluster Sets and Ashwagandha: This Week's Training Science

> This week on PubMed: creatine, cluster sets, ashwagandha and training timing, broken down simply for your time in the gym.

- Source: [Musku](https://musku.app/), free strength training tracker for iPhone and Android
- Canonical URL: https://musku.app/blog/research-roundup-lifting-2026-09-27
- Published: 2026-09-28
- Updated: 2026-09-28
- Level: Beginner, Intermediate, Advanced
- Language: English
- French version: https://musku.app/fr/blog/veille-scientifique-musculation-2026-09-27
- Author: Musku (Julien Legrand)

_Informational content: this is not a substitute for medical advice. Check with a doctor before starting a training program, especially if you have a health issue or any pain._

This week we went through PubMed so you don't have to, and pulled four studies that speak directly to what happens in the gym: creatine, how you structure your sets, a trendy supplement, and the age-old debate about the "best" time of day to train.

## Creatine still delivers when paired with resistance training

A three-level meta-analysis pooled 63 studies and 1,489 participants comparing resistance training alone with resistance training plus creatine supplementation, tracking upper- and lower-body strength, lean mass, fat mass and total body weight.

Adding creatine boosted upper-body strength (g = 0.54) and lower-body strength (g = 0.55), increased lean mass (g = 0.30), and slightly lowered body-fat percentage (g = -0.14), with no significant change in absolute fat mass. The small increase in total body weight (g = 0.12) was driven by lean mass, not fat. An exploratory analysis hinted that strength gains might be larger in younger participants, but the authors themselves flag this as tentative, since the age subgroups weren't evenly represented.

In practice, this confirms what the evidence has said for years: creatine remains one of the few supplements with a clear, reproducible effect on strength and lean mass when paired with real resistance training. Nothing new here, but worth the reminder.

**Limitations:** the 63 included studies varied a lot in dosing, frequency, duration and participants' nutritional intake, which complicates direct comparisons, and the age-related findings remain exploratory.

## Cluster sets vs. rest-redistribution: two ways to protect your bar speed

A systematic review paired with a Bayesian network meta-analysis pulled together 37 studies comparing three ways to structure your sets: traditional continuous sets, cluster sets (short pauses inserted within a set), and rest-redistribution (splitting rest within or between sets).

All three alternative structures preserved average bar velocity better than traditional sets, with effect sizes from 0.41 to 0.60. For peak velocity, cluster sets and within-set rest-redistribution also beat traditional sets, while between-set rest-redistribution didn't clearly separate from it. Head-to-head, the three alternative methods performed similarly overall, though cluster sets edged ahead slightly by statistical ranking (SUCRA).

For your training, that means if your goal is to keep bar speed and power output high across a set, for example on force-velocity focused work, splitting your rest inside the set rather than banking it all at the end can help you keep execution quality from the first rep to the last.

**Limitations:** these are acute velocity effects, not long-term strength or hypertrophy outcomes, and the search only covered two databases.

## Sustained-release ashwagandha: a strong signal, still from a single trial

A randomized, double-blind, placebo-controlled trial tested a sustained-release ashwagandha formulation (300 mg/day) in 84 healthy, recreationally active adults over 90 days, tracking bench press 1RM, VO2max, blood markers and quality of life.

The supplement group pulled ahead of placebo as early as day 30, with the gap widening by day 91: +15.31 kg on bench press 1RM versus +7.33 kg for placebo, and a VO2max increase of 30.56 versus 18.14 mL/kg/min (p

These are striking numbers, but this work suggests an effect rather than proving it beyond doubt: it's a single trial, run by a team with a direct commercial interest in the outcome, and it needs independent replication before it becomes a firm recommendation.

**Worth flagging:** ashwagandha affects hormone levels and isn't neutral if you have a thyroid or hormonal condition, or are pregnant. If you're on medication or managing a health condition, check with a healthcare professional before adding this kind of supplement.

**Limitations:** a single trial with a modest sample (84 people), in a "recreationally active" population rather than experienced lifters, which limits how far these results generalize to a more advanced audience.

## Training in the morning or the evening: individual timing barely moves the needle

A randomized controlled trial followed 108 older adults (average age 67, 93 analyzed) to test whether training at your own daily performance peak, identified through repeated testing at 8am, noon, 4pm and 8pm, produces better results than training at your personal trough, over a 12-week, twice-weekly resistance program.

Result: no significant difference between groups on isometric thigh strength, handgrip strength or appendicular lean mass index, with every confidence interval overlapping zero.

In practice, if you've been wondering whether you absolutely have to train at "your best time of day" to make progress, this work suggests you don't: schedule your sessions when your day actually allows it rather than chasing a theoretically optimal slot.

**Limitations:** the study looked at adults over 60 across just 12 weeks, which limits how directly it applies to younger lifters or longer training blocks.

## Sources

- "Resistance training combined with creatine supplementation: a three-level meta-analysis of multidimensional outcomes from strength enhancement to body composition remodeling", Journal of the International Society of Sports Nutrition, [10.1080/15502783.2026.2718316](https://doi.org/10.1080/15502783.2026.2718316)
- "The Effectiveness of Cluster vs. Rest-Redistribution Set Configurations to Maintain Movement Velocity During Resistance Training: A Systematic Review and Bayesian Network Meta-analysis", Sports Medicine - Open, [10.1186/s40798-026-01106-w](https://doi.org/10.1186/s40798-026-01106-w)
- "Efficacy and safety of a sustained release ashwagandha root extract capsules on muscle strength and cardiorespiratory endurance in recreationally active individuals: a randomized, double-blind, placebo-controlled trial", Frontiers in Nutrition, [10.3389/fnut.2026.1919322](https://doi.org/10.3389/fnut.2026.1919322)
- "Effects of Daily Rhythm-Aligned Training on Skeletal Muscle Adaptation in Older Adults: A Randomized Controlled Trial", Journal of Cachexia, Sarcopenia and Muscle, [10.1002/jcsm.70390](https://doi.org/10.1002/jcsm.70390)

## Frequently asked questions

### Does creatine actually make you gain fat?

No, this meta-analysis shows the opposite: the weight gain observed came from lean mass, and body-fat percentage actually dropped slightly in supplemented participants.

### Do I need to change how I structure my sets to progress faster?

Only if your goal is maintaining bar speed on force-velocity work. For classic hypertrophy training, traditional sets remain a perfectly valid base; cluster sets are an extra tool, not a mandatory replacement.

### Is ashwagandha safe to take?

This trial's results are encouraging but still come from a single study, and the supplement affects hormone levels. Check with a healthcare professional before starting, especially if you have a thyroid or hormonal condition or are already on medication.

### Is morning or evening training better?

Based on this study in older adults, it barely matters for medium-term results. The best time to train is whichever one you can actually stick to.

Whether you're logging your sets and loads in Musku, timing your rest between cluster sets with the built-in rest timer, or watching your estimated 1RM (via the Epley formula) trend over the weeks, this week's studies mostly give you one thing: a bit more perspective to fine-tune your choices, without needing to overhaul your whole routine overnight.