String hook in archery: three fingers hold the string at the 2nd and 3rd joint, the DSB model load split of 40/50/10, and the typical mistakes.
The honest answer up front: in the hook, the string rests between the 2nd and 3rd finger joint on three fingers, and you hold that position until the release. That is how the German Shooting Federation's position-phase model for recurve describes it [1]. The fingers are not a hook for yanking but a holder that you open at the moment of release.
Why does it matter? At full draw the string carries the bow's whole load on three fingers. The more constant your fingers sit, the more constant the arrow starts. A lab analysis of finger movement in one top Austrian archer showed that the middle finger varied more in its joint angles on bad shots than on good ones [3]. That is a single-case study, but it matches practice: a wobbly hook makes a wobbly release.
How hard is it? You learn the finger position in an hour. It stays correct when your grip stays stable during the draw. In experience terms it takes weeks until your hook also holds under fatigue. Be patient with yourself: your body has to learn that the fingers hold and do not pull.
A quick note up front: measurements on 15 skilled archers showed that even experienced archers use different patterns at release. About half relaxed the fingers, the other half actively extended them [5]. So there is no single correct finger-muscle trick. What matters is that your pattern is the same in every shot.
Place index, middle and ring finger on the string so that it lies between the 2nd and 3rd finger joint [1]. That is roughly the first joint behind the fingertip, not the tip itself. Milestone: your coach sees in every shot that the string sits in the same place.
The DSB model gives a load of about 40% on the index finger, 50% on the middle finger and 10% on the ring finger [1]. So the middle finger carries the most, the ring finger the least. Anchor: if one finger works too hard, you notice it as burning at the fingertip or as cramping.
The thumb rests in the palm and the little finger is angled [1]. Neither interferes with the string. They stop the hand from opening or splaying.
The draw hand stands vertical, straight to slightly overextended, at about navel height [1]. That means the wrist does not bend.
The finger position stays until the string slides through the fingers [1]. Do not open the fingers early, and do not let them give way. Milestone: in 10 consecutive shots the hand stays calm on video until the arrow has left.
Film not just the draw but the draw hand at full draw, in slow motion, from the front. If you see that all three fingers carry the load evenly and nothing shifts, you can concentrate on the rest. If you see the fingers giving way just before release, that is your first lever. Do a short series with light draw weight and just this one task: set the fingers, hold, check the video.
Between the 2nd and 3rd joint of the index, middle and ring finger [1]. That is the joint behind the fingertip. The position is held until release.
According to the DSB model, the middle finger with about 50%, then the index finger with 40% and the ring finger with 10% [1]. This is a teaching model, not a measured value for every hand.
The model describes the string sliding through the relaxing fingers [1]. Measurements on 15 skilled archers showed two patterns: in 8 archers the activity of flexors and extensors dropped, in 7 the extensor activity rose before release [5].
With finger protection, a suitable load split and a draw weight you hold under control. Tab, glove and fingertips are allowed [2].
Mediterranean Draw (Split Finger): The Standard for Sighted Recurve