If you're running a splined crank & have recently removed it, check for bits that may have cracked off the crankarm (where the crankarm interfaces with the splines on the bb axle) that may be sitting in there & causing the crankarm to creak / loosen. Have seen this happen when cranks have been removed & re-installed repeatedly.
If you're running a splined crank & have recently removed it, check for bits that may have cracked off the crankarm (where the crankarm interfaces with the splines on the bb axle) that may be sitting in there & causing the crankarm to creak / loosen. Have seen this happen when cranks have been removed & re-installed repeatedly.