Adductor longus

What it is

A flat, triangular muscle on the front of the inner thigh, the most superficial and most visible of the adductor group. It runs from a narrow origin on the front of the pubis, fanning out to attach along the middle of the back of the femur.

Its upper edge forms the medial border of the femoral triangle, with sartorius on the other side.

Adductor brevis lies immediately behind it, and adductor magnus behind that.

What it does

Adducts the hip. It also assists in flexing the hip, because its origin sits in front of the joint's axis, and it contributes to rotation in a way that depends on the position of the hip — which is why sources disagree about whether it rotates the thigh in or out. Both answers appear in the literature and the honest version is that it depends on where the hip already is.

What loads it

Movements bringing the legs together under resistance, and hip flexion combined with adduction. Kicking, skating, and changes of direction in field sport load it hard.

Squatting loads it as part of the group; the goblet squat does so particularly at depth.

What is commonly got wrong about it

That adductor strains are minor. Injury here is common in football and other sports involving kicking and rapid direction change, and this is the adductor most frequently involved. It has a reputation for being slow to settle.

"Groin" as an anatomical location. It is a region, not a structure, and pain there can originate in muscle, tendon, the pubic bones, the hip joint, or the abdominal wall — several of which are not treatable by anything on this site.

That the inner thigh is trained by machines only. Any squat, lunge or split stance loads the adductors, and the wider the stance the more so.