Tel's Tales is the column written by three-times Olympic rowing coach Terry O'Neill. This week he covers the new force time curve function in the PM3. If you've got a question, query or quibble you'd like him to answer, send it to tels-tales@therowingcompany.com.The new PM3 has a facility to display the rower's force time curve. As the name suggests this is a graph of time along the X-axis (horizontal), against force on the Y-axis (vertical). The time starts at the beginning of the drive phase of the stroke and ends at the finish of the drive phase. At the beginning of the drive phase, the rower has changed direction from coming forward on the recovery to moving backwards during the drive. At the point of the change of direction, the rower is stationary and so there is zero force applied at the beginning of the stroke. On the PM3, the beginning of the curve does not start at zero and this is because of the way the information is gathered, which requires several revolutions of the flywheel.As the rower gathers momentum along the slide, the force applied increases to a maximum. The flywheel accelerates as a result of the applied force and, as a consequence, the force that can be applied to the flywheel decreases. The resultant curve, therefore, should rise to a peak before decaying back to zero at the finish. The line of the curve should be smooth without any steps or spikes along its outline.Where any distortion to the smooth outline of the curve can be seen it can be attributed to a fault in the technique. The most common faults are driving the legs down too hard, which will cause the force time curve to rise sharply but then start to decrease before climbing again and following the normal path. This type of curve is most commonly seen amongst woman and can be attributed to lack of upper body strength compared to the strength in the legs.The second most common fault is a step up or plateau just before the finish. This is more common amongst male rowers and is caused by not using the legs properly at the beginning of the drive and then tugging the finish into the body at the end of the stroke.The area under the curve represents the total power applied during the stroke. The more power applied, the faster you will spin the flywheel. The area can be increased in two ways: increasing the force (pulling harder), or applying the force for more time (rowing longer).There can be other variations in the shape of the curve, most notably in the time it takes to reach peak force. These variations are important for on water rowers when selecting crews but less so for indoor rowers where the most important element is the area under the curve.