BioRowTech - What is it for?

The three most typical mistakes in rowing technique, which have the largest impact on performance, can be seen and corrected both on the water and on the rowing machine:

"Opening up"(or rolling) of the trunk at the catch “locks” the knees at their sharpest angle, which makes the work for the quadriceps very hard, stops the rower’s CM (in global coordinates) and increases the variation of its velocity and inertial losses of energy. This could also be harmful for knee joints.
“Grabbing” the arms and shoulders during the first part of the drive, or a too early “opening” of the trunk activates smaller arm muscles and limits acceleration of rower’s mass, which significantly decreases rowing effectiveness. Leg and arm muscles, as well as ligaments and joints could be overloaded and injured.
“Throwing” the trunk after the finish of the drive (prolongation of shoulder movement to the bow, when the handle has already changed direction and moves to the stern) means that the kinetic energy of the trunk was not utilised into blade propulsion, but was lost in the rower-boat system. This overloads the abdominal muscles and quadriceps, and could be a cause of rib stress fracture at high stroke rates.

How does it work?

Our new BioRowTech system for the rowing ergometer can help you work on the problems above, and can be used as a complete instrument for rowing technique analysis and correction. It measures three variables: the positions of the handle, seat and trunk (at the level of the shoulder joint). The velocities of the legs (seat), trunk and arms are derived from measured positions and are used in comprehensive analysis, which produces the following three indicators displayed instantly for the rower to see:

1. Catch Factor is the time difference between the instant of the handle changing direction and the instant of the seat changing direction, at the catch. The optimal value is -25ms (-0.025s): by this time the seat should 'overtake' the handle at the catch, which allows use of the legs for the initial movement at the catch and for the acceleration of the rower’s mass. Positive values (red zone) mean the rower is opening up with the trunk, or 'grabbing' the arms and shoulders; extremely negative values below -50ms (blue zone) indicate 'slide shooting' (known as 'bum shoving') at the catch, leading to losses in leg power.

2. Rowing Style Factor is the ratio of the seat travel to the handle travel during the first 20% of the drive length (from the catch until the 'transition point', RBN 2015/10). The optimal value is 90%, which means only 10% of the handle movement should be provided by the upper body and the main contribution should come from the legs. Values lower than 80% (red zone) indicate grabbing in the arms/shoulders or a too early opening of the trunk. Values higher than 100% (blue zone) mean the legs are going off too fast (bum shoving) and losing the power through a weaker back.

3. Finish Factor is the time difference between the instant of the changing direction of the trunk and changing direction of the handle, at the finish. The optimal value is -50ms (-0.05s). By this time the “return” of the trunk should overtake the stopping handle. Positive values (red zone) mean 'throwing' of the trunk after the finish; negative values lower than -100ms (blue zone) mean the rower is winding the trunk around the handle, and is losing trunk power at the finish.

The three indicators above are displayed each stroke on the left side of the screen. On the right side, four curves are displayed: these show the velocities of the legs, trunk (between seat and shoulders) and arms, as well as handle velocity, which is the sum of the other three segment's velocities. The curves are displayed relative to the handle position on the x-axis, so they make loops around the axis where the drive phase is represented above the axis, and the recovery below it. The visual shape of the curves is complimentary to the indicators, and may help to understand better the specifics of rowing technique.

The BioRowTech system is quite a simple but effective tool for rowing technique improvement for rowers of all levels. For experts, it gives a lot of detailed information, for example the contribution of body segments into total stroke length, values and curves of segment velocities, etc. The system works with a modified BioRowTel software under Windows, which allows the recording of data samples, production of average curves, and analysis of differences between various rowers and data samples.

Product details

The system is supplied in a plastic box, which has two layers: a tablet PC at the top, and three sensors connected to a data collector at the bottom. The sensor called the “string pot” is a compact cylinder with a spring-loaded string coming out of it. Two strings from the sensors are connected to the handle and seat, and one is left taut and is connected to the clothing of the rower at shoulder level when the erg is being used. The strings create less than 100g of tension, which goes practically unnoticed by the rower.

The software is preinstalled on the Tablet PC, so you need only turn it on, connect the Data Collector and sensors, and start using the system.

3M Double-Lock tape is also provided to attach the sensors to the erg.

Installation (also see videos at end of this description)

The sensors are mounted on the frame of the rowing machine using 3M Double-Lock tape, which provides strong fixation, as well as quick removal and reinstallation in future uses. The picture below shows installation on the Concept2 (a) and RP3 (b) rowing machines.

The handle sensor (1) is mounted on the frame close to the cog-wheel, and is connected with the string to the handle using the String Adjuster and velcro strip. During the drive, the wire should be approximately parallel to the chain.

The seat position sensor (2) is mounted in the middle of the foot stretcher. Similarly, the String Adjuster is attached at the bottom of the seat, so that the wire is parallel to the travel of the seat.

The trunk position sensor (3) is mounted on the monitor arm of the erg.. The string of the sensor is connected with the athlete’s clothes at shoulder level.

The Data Collector (4) is mounted on the frame, then the sensor cables should be made tidy using some sticky tape. Mount the tablet PC, turn it on and connect the cable to micro-USB socket B, which will power the Data Collector (a blue LED will start flashing).

In all the sensors, use the automatic string adjusters to prevent string damage: it releases the string if the load exceeds about 0.5kg. In the trunk sensor, it helps to adjust the range of the string to the range of the shoulder movement, the adjusted string should be extended by 20-40 cm, so the end of the string should never touch the sensor (there should always be a 5-10cm gap from the furthest shoulder position at catch). To wind the string back, remove the tension and push the button on the string adjusters, its internal coil will pull the string inside.