Squat strength rose 25% in six weeks while the movement pattern barely changed
In short
A group squatting three times a week — five sets of ten at 75% of one-rep max — gained 24.87 ± 7.36% in strength over six weeks, but the muscle synergies extracted from EMG of seven lower-limb muscles stayed essentially the same, with only slight shifts in how individual muscles were weighted. Powerlifters and weightlifters with two or more years of training showed something different: the timing of the synergies itself had changed, with the first synergy delayed, the second brought forward, and different contributions from the muscles around the ankle. Coordination reorganises over years, not weeks.
Participants who squatted three times a week for six weeks — five sets of ten at 75% of one-rep max, load progressed throughout — got 24.87 ± 7.36% stronger. When EMG from seven lower-limb muscles was used to ask how their squat had changed over that time, the answer was: barely at all.
Measurements were taken across four loads between 40 and 90% of one-rep max — light (~42.5%), moderate-light (~57.5%), moderate-heavy (~72.5%) and heavy (~87.5%). At every load, two muscle synergies accounted for at least 90% of muscle activation. After six weeks of training that two-synergy structure was still there; only the weighting of individual muscles within it had shifted slightly.
Where does the early strength gain come from, then?
Not from rewriting the coordination pattern but from driving the existing one harder. The order and combination in which muscles fire holds; the output of that combination rises. This is also why a beginner's numbers climb far faster than their muscle size does.
What is different about experienced lifters?
The study compared three groups: 11 untrained people, 11 who completed the six-week programme, and 10 powerlifters and weightlifters with at least two years of experience. Only the experienced group differed structurally — the first synergy was delayed, the second anticipated, and the muscles acting around the ankle carried different weight. Nothing like it appeared in the six-week group.
So how should this change training?
Holding load back while waiting for technique to improve on its own has weak support here. Coordination does not reorganise in six weeks, so what those weeks can do is groove a safe pattern and progress the load. The flip side matters more: whatever pattern you repeat is the pattern that gets reinforced. The old advice about fixing form before chasing weight has an EMG-level version of itself in this data.
The shift in ankle-muscle contribution among experienced lifters is a practical hint — it lines up with ankle mobility being a common bottleneck on squat depth. The distinction between mobility and flexibility is covered in mobility versus flexibility.
If you track a relative strength score, this explains the shape of the early curve. The fast climb over the first few months is not proportional muscle growth; it is the nervous system driving an unchanged pattern harder. The slowdown that follows is normal, not a failure. See muscle size and strength for the other half of that relationship.
This is a small study — 10 to 11 people per group. Muscle synergy analysis extracts patterns statistically from EMG, so results depend on which muscles were instrumented. Take the direction, not the individual numbers.
Frequently asked questions
How much strength do you gain from six weeks of squat training?
In this study, a group squatting three times a week at 75% of one-rep max for five sets of ten gained an average of 24.87 ± 7.36% in strength over six weeks. The coordination pattern of their leg muscles barely changed over the same period.
Why do beginners get strong so quickly?
Because early gains come from driving the existing muscle coordination pattern harder rather than rewriting it. Over six weeks of squat training the muscle synergy structure stayed intact while strength rose about 25%.
How does an experienced lifter's squat differ neurologically from a beginner's?
Lifters with two or more years of training showed a timing difference — the first muscle synergy delayed and the second anticipated — plus different contributions from the muscles around the ankle. Six weeks of training did not produce that difference.
Does squat form improve on its own as you add weight?
Do not count on it. Six weeks of training did not reorganise coordination, and repetition reinforces whatever pattern you currently use. Correcting form is better done before loading heavily rather than after.
Source: PubMed