Control the curl instead of hoping: set in-turn and out-turn cleanly, read how much the ice bends and steer the path with weight and sweeping.
You create the curl with a gentle quarter turn of the handle at the moment of release — for a right-hander the in-turn runs clockwise, the out-turn counter-clockwise [1]. No more, no less. The stone bends on its own after that; your job is only to give it the rotation cleanly and to know how far this ice bends today.
And now the part almost nobody says out loud: why the stone curls is still not scientifically settled [1]. The obvious explanation — more friction at the back than the front — does not add up: even assigning all the friction to the trailing half yields only about half the sideways displacement actually observed [2]. Competing models such as the scratch-guide mechanism (the running band scratches fine grooves into the ice, tilted one way or the other depending on rotation, which then guide the stone), the pivot-slide model or the snowplough explanation still stand side by side [2].
Sounds academic, isn't: researchers were able to steer stones onto a zigzag path purely by laying artificial scratches into the ice [2]. So if the curl surprises you occasionally, you are in good company — it still surprises physics too.
For you as an advancing player what counts is therefore not the theory but the amount of curl on your ice: championship ice typically bends draws five to six feet, club ice closer to four [3]. That is the difference between "past the guard" and "stuck on the guard".
Depending on the turn, the handle starts slightly rotated and reaches neutral by release: one quarter turn, gentle, from the wrist [1]. Do not crank it. More rotation does not mean more curl — it only makes the stone restless. As a coaching experience value: two and a half to three and a half revolutions over the run from hog line to hog line; if your stone spins like a top, you are over-rotating.
For a right-hander the in-turn runs clockwise and pulls the stone from outside inwards, the out-turn counter-clockwise and pulls it outwards [1]. The difference does not live only in the hand but in how your whole body aligns to the target [4]. Always practise both turns in pairs, never just your favourite.
Play five draws with in-turn and five with out-turn to the same point and measure how far each drifts sideways. That is today's amount of curl. For orientation: championship ice five to six feet, club ice around four [3]. Pass that number to your skip — it is the basis of every call.
Sweeping creates frictional heat and with it a thin film of water; the stone then runs farther and straighter, so it curls less [1]. And the dose is controllable: doubling the downward force doubles the heat generated, while doubling speed yields only a factor of 1.55 [5]. Sweeping is therefore not an emergency button but your second steering wheel.
The amount of curl is not a constant. The pebble — the fine sprayed droplets the stone runs on — breaks down, and the sheet gets faster from the second or third end [3]. Freshly prepared and nipped ice (where the pebble tips are cut flat) runs faster and curls more [3]. So recalibrate mentally every second end.
Rotation training tempts you into many repetitions with little rest — and that is exactly where technique tips into overuse. On every stone, watch the straight back in the deep position and make sure the rotation comes from the wrist, not from twisting the shoulder.
When you alternate in-turn and out-turn in block training, your alignment in the hack changes too. Reset the sliding foot deliberately instead of twisting your body mid-slide — twisting under load is the shortest route to back and hip complaints.
And still: this guide explains mechanics and control and never replaces the supervised course. A coach's eye sees within two stones whether your rotation comes from the hand or the shoulder.
Lay two brooms across the sheet as goalposts, exactly where your stone should pass according to your curl calculation — usually one to two metres before the house. Then play ten draws and care only about whether the stone runs through the gate, not whether it stops in the house. That separates reading the curl from weight errors and shows within one session whether you really understand your ice. Hit the gate and from the next end on you play on a call instead of on hope.
They are the two directions of rotation you give the stone with a quarter turn of the handle. For a right-hander the in-turn runs clockwise and pulls the stone inwards, the out-turn counter-clockwise and pulls it outwards [1]. Both should sit equally well — in a game you need them alternately.
Through a clean, gentle quarter turn of the handle at the moment of release, not through force [1]. More rotation creates no additional curl, it only makes the run restless. The ice does the rest — and how far it bends you measure with a few calibration stones at the start.
That depends on the ice. On championship ice a draw typically bends five to six feet, on club ice closer to four [3]. The value also drifts during a game, because the pebble breaks down and the sheet gets faster from the second or third end [3].
Honest answer: that is still not settled scientifically [1]. The classic explanation via asymmetric friction accounts for only about half of the observed sideways movement [2]. Competing models such as the scratch-guide mechanism sit alongside it — researchers were even able to steer stones in a zigzag using artificial scratches [2].
Curling Tactics: Guard, Takeout, Freeze and When the Hammer Turns Into Points