Soleus strength rose and held through a football season; injury, age and sex were linked to lower strength
In short
In 41 Australian footballers, soleus-focused absolute strength rose from 121.7 kg preseason to 135.2 kg early in the season and remained at 135.8 kg late in the season. Relative strength progressed from 1.51 to 1.69 to 1.75 times body mass. Recent calf injury, older age and female sex were associated with lower strength; these associations do not establish causes.
A season of football did not coincide with declining soleus-focused strength in this sample: strength increased early and stayed elevated late. The study in the Journal of Strength and Conditioning Research followed 41 state-league Australian footballers, 32 men and 9 women, from 3 teams across one season, collecting 210 strength measurements.
What did the soleus strength test measure?
Athletes performed a seated, flexed-knee maximal plantar flexion: pushing the forefoot down as hard as possible with the knee bent. That position biases the soleus rather than isolating it completely. Relative strength = force ÷ body mass. The test's reported kg values should not be treated as interchangeable with the load on a calf-raise machine.
How did preseason, early-season and late-season results compare?
Absolute strength averaged 121.7 ± 27 kg preseason, 135.2 ± 27.3 kg early in the season and 135.8 ± 25.9 kg late in the season. Relative values were 1.51 ± 0.28, 1.69 ± 0.27 and 1.75 ± 0.26 times body mass. The longitudinal model reported β = 19.33 kg for absolute strength and β = 0.24 BM for relative strength, both p < 0.001; those coefficients are distinct from simple differences between group means.
What do injury history, age and sex tell us?
Recent calf injury history (p < 0.001) and older age (p = 0.03) were associated with lower strength. Women had lower absolute strength (β = −23.53 kg) and relative strength (β = −0.22 BM), both p < 0.05, plus greater side-to-side asymmetry (β = 8.13 kg, p = 0.01). These are group associations, not individual ceilings or explanations of what causes calf injury.
What should lifters log in fairlift?
The seated calf raise is a practical exercise matching the bent-knee position. Record load and reps per side in fairlift's workout log, keeping the machine and range of motion consistent when tracking asymmetry. After a calf injury, compare with your own pre-injury baseline rather than chasing the study average. The Muscle Index covers only squat, bench press and deadlift, so calf work stays a separately tracked accessory. See also progress beyond adding weight.
This observational study cannot show that playing through a season or doing a particular exercise caused the gains. The abstract does not report an effect of calf-focused resistance training, and the athletes' averages are not individual rehabilitation clearance targets.
Frequently asked questions
Does soleus strength decline over a season?
In this study of 41 Australian footballers, soleus-focused absolute strength rose from 121.7 kg preseason to 135.2 kg early in the season and held at 135.8 kg late in the season. That pattern is not a guarantee for every athlete or recreational lifter.
What are the soleus strength test and relative strength?
The test is seated maximal plantar flexion with a bent knee, which biases the soleus. Relative strength is force ÷ body mass and averaged 1.51, 1.69 and 1.75 times body mass at preseason, early-season and late-season testing. Test readings are not equivalent to seated calf-raise machine loads.
How were recent injury, age and sex related to strength?
Recent calf injury history (p < 0.001) and older age (p = 0.03) were associated with lower strength. Women had lower absolute strength (β = −23.53 kg) and relative strength (β = −0.22 BM), both p < 0.05, and greater asymmetry (β = 8.13 kg, p = 0.01). These group associations establish neither causation nor an individual's strength ceiling.
Can seated calf raises be credited with the strength gains?
This observational study cannot establish that seated calf raises caused the gains. The abstract does not report an effect of calf-focused resistance training. Seated calf raises are a practical exercise choice because they match the test's bent-knee position.
How should fairlift records be compared after a calf injury?
Log seated calf-raise load and reps per side in fairlift's workout log, then compare with your own pre-injury baseline and track asymmetry under consistent conditions. The Muscle Index covers only squat, bench press and deadlift, so calf work is tracked separately as an accessory. The study averages alone cannot establish rehabilitation readiness.