Rowing Factors FAQs

Rowing Factors FAQs

The Catch and Rowing Style Factors are important parts of the BioRow reports, but rowers and coaches often ask about their meaning. This newsletter should clear up these common queries as well as offer practical advice.

Q: What is the Catch Factor?

A: In Rowing Biomechanics, the catch is defined as the moment in time when the handle changes direction at the end of the recovery – the start of the drive (please do not confuse the “catch” with the “entry” into the water). At this moment T0h (Fig.1), the handle velocity crosses the zero line from negative values to the positive. Similarly, the moment of the seat changing direction T0s can be defined.

The Catch Factor CF is defined as the difference (in milliseconds, 1ms=0.001s) between T0h and T0s:

CF = T0h - T0s                                           (1)

The optimal CF is negative with a value of -15ms in sculling and -25ms in sweep: meaning that the seat should change direction earlier than the handle at the catch (Fig.1,a). This allows for the use of legs for the initial movement at the catch thus providing fast acceleration of the rower’s mass. Positive CF values (Fig.1,b) are related to “opening up” with the trunk, or “grabbing” the arms/shoulders at catch. Extremely negative CF values below -50ms indicate too much “bounce” out of with the seat, which wastes leg power and creates problems for other rowers in a boat.

Q: Does the earlier seat movement at the target Catch Factor mean “slide shooting”?

A: No. During the very short CF target time -15/-25ms, the seat moves to the bow only about 1-2cm before the catch, but this is enough to give initial acceleration to the rower’s mass and provide a solid dynamic drive. Only extremely negative CF values below -50ms can be called “slide shooting” because the seat travels about 5-6cm in this case, so productive legs work gets shorter by this distance.

Q: What is Rowing Style Factor?

A: Rowing Style Factor RSF is defined as the ratio of the seat travel to handle travel during the first 20% of the drive length (from catch to “transition point”, RBN 2008/07, 2013/07). The optimal value RSF is 90% (Fig.2,b), which means only 10% of the handle movement should be provided by upper body, and the main contribution 90% comes from the legs. RSF values lower than 80% (Fig.2,a) indicate “grabbing” of the arms/shoulders or too early “opening” the trunk during the drive. RSF higher than 100% (Fig.2,c) means legs are going off too fast (“bum shoving”) and  the back is in a weaker position that does not hold the pressure, concedes and wastes legs power.

Q: What is the difference between the Catch and Rowing Style Factors? How are they related?

A: Both CF and RSF indicate coordination of legs and upper body, but they are not the same: there is no functional dependence between them, only a mild correlation (r=-0.32). This means that rowers with a more negative CF (earlier change direction at the seat) tend to produce higher RSF numbers – faster legs drive, and vice versa. However, there are many exceptions: negative CF could be followed by early trunk “opening” and low RSF, and vice versa: early “grabbing” the handle at catch with positive CF is followed by fast legs drive and even “slide shooting” with high RSF.

Generally, the Catch Factor CF indicates TIMING of the handle and seat coordination. The blade is still in the air at the catch, velocities are close to zero, so movements are small.

The Rowing Style Factor RSF indicates relative SPEED of the seat and handle movements during the beginning of the drive.

Q: How do you improve the Catch Factor?

As the most common mistake is positive CF – late changing direction of the seat at catch, the first thought to fix it is to move the seat earlier. However, this doesn’t work practically and leads to shorter catch angles. It is much better to approach it from other end: to change direction of the handle later, and start the drive by working fast with the legs through the stretcher and hang off the handle instead of pulling it.

©2022 Dr. Valery Kleshnev