We hope this list of questions/answers is helpful. If you have a question that isn’t answered below, please email us.
The force and video data reinforce the positive elements of a swimmer’s technique and identify factors that limit performance. The display shows how well force is applied to the water, at what point in the stroke there is a force loss or wasted motion, and the difference between the left and right hands. A review of the synchronized force and video information shows the swimmer what changes are necessary to improve.
Hand force is the single most important factor in swimming propulsion. It is directly related to swimming speed
Virtually all swimmers (even the fastest in the world) lose force at some point in their stroke (sometimes as much as 20 lbs!), waste motion (typically .25 sec or more!) and have bilateral differences (usually at least 15%!). Aquanex+Video is the only way to get this information.
Aquanex sensors are placed on the swimmer’s hands. Video and force data are collected over a 10 yard swim towards an underwater camera.
A front underwater view video clip is collected as an avi file. The sensors measure force throughout each stroke and display the force variations on the computer screen. After the swim, Aquanex automatically calculates swimming velocity, stroke length, and stroke rate, as well as the peak force, average force, pull time, and recovery time of each stroke.
Force curves are similar to fingerprints in that each person’s curves are unique. There are general tendencies that can be seen in many curves, but each swimmer has individual characteristics.
Swimmers generally exert the most force in freestyle, followed by butterfly, breaststroke, and backstroke. This order is consistent with the relative mechanical advantage afforded by each stroke. If a swimmer has a different order, they are not effectively utilizing their strength in all strokes.
The validity of using Aquanex for measuring performance in aquatics was established in many experiments. The force values were higher for competitive swimmers than non-competitive, for faster swimmers than slower swimmers, after being coached than before, and after taper than before. Experiments were also conducted using Aquanex for aquatic therapy. Higher force values were found post-rehab, post-training, and for the uninjured side. Force values were found to be higher for males than females, for normal subjects than patients, for leg movements than arm movements, for adduction than abduction, and for internal rotation than external rotation. In every manner in which Aquanex has been tested, the results have supported Aquanex as a valid instrument for measuring force and time variables.
A comparison of data from successive sessions can be used to determine the effectiveness of technique changes. Some swimmers make impressive changes in only a week. The best guideline is to retest when a swimmer thinks a change has been made.
Monitoring force variations over a season provides coaches with information about how a swimmer is responding to both the heaviest workload and to the rest at the end of a season. This information is vital to making adjustments in a swimmer’s workload.
The analysis is usually conducted by Dr. Rod Havriluk (the inventor of Aquanex and the president of STR). Dr. Havriluk has analyzed thousands of swimmers, including Olympians, world champions, and world record holders. He is a biomechanist and a former college, age group, and YMCA coach. He taught biomechanics at Indiana University and Florida State University and has presented his research at conferences and coaching clinics all over the world. Feedback sessions can be conducted for swimmers or coaches.
Aquanex+Video testing with a feedback session, a playback version of the Aquanex software, and the swimmer’s data files is based on location, dates, and number of participants.
For swimmers who have never been tested with Aquanex+Video, the four stroke option will provide information about force variations between strokes. This information is invaluable, as swimmers often find that they are less competitive in one stroke because they are not using their strength in the same way that they are in the other strokes.