Aquanex has been used in a variety of clinical and research projects in swimming and aquatic therapy over the last 20 years. Aquanex sensors measured force on the hands, feet, paddles, fins, and several types of aquatic exercise equipment. Many of the studies have resulted in presentations and publications. Copies of most manuscripts are available on request.

Aquanex data are reliable and valid.

The initial research on Aquanex showed that the system was reliable (measured the same value on repeated trials) and valid (measured the value that it was meant to measure). The validity was supported by a series of three experiments that found a greater force value: for competitive swimmers than recreational swimmers; for swimmers treated with an instructional intervention than without the intervention; and after being coached than before.

Havriluk, R. (1988). Validation of a criterion measure for swimming technique. Journal of Swimming Research, 4(4), 11-16.

Strength increases with aquatic rehabilitation.

The validity of Aquanex was also demonstrated in aquatic rehab. A series of experiments demonstrated a strength increase as an expected benefit of a rehab program using Aquanex to measure the improvement.

Prins, J. H. & Havriluk, R. (1991). Measurement of changes in muscular strength in aquatic rehabilitation. Paper presented at the XIIth International Congress on Biomechanics, Perth, Australia, December.

Luis, C. (1992). Rowdy Gaines: only a few laps from recovery. Swim, 8(2), 22-26.

Prins, J. H., Merritt, D. J., Blancq, R. J., Goebert, D. A., & Hartung, G. H. (1992). Effects of aquatic exercise training on muscle force in sedentary persons with polio disability. (Abstract)  Medicine and Science in Sports and Exercise, 24(5), S34.

Prins, J. H., Hartung, G. H., Merritt, D. J., Blancq, R. J., & Goebert, D. A. (1994). Effects of aquatic exercise training in persons with poliomyelitis disability. Sports Medicine, Training and Rehabilitation, 5, 1-11.

Prins, J. H., & Lally, D. A. (1995). The measurement of applied hydrodynamic forces in aquatic rehabilitation. Paper presented at the XIIth World Congress of IFPMR, Sydney, Australia, March.

Faster swimmers have a more effective technique than slower swimmers.

Faster swimmers were found to have a more effective technique than slower swimmers, as indicated by a lower active drag coefficient. The results also showed an improvement in technique with age. However, the improvement leveled off for teenagers, showing a need for continued technique analysis and instruction. The coefficient of active drag was found to be a valid measure for the effectiveness of swimming technique.

Havriluk, R. (2003). Performance level differences in swimming drag coefficient. In VIIth IOC Olympic World Congress on Sport Sciences. Athens: IOC Medical Commission, 93E.

Hand force is directly related to swimming velocity.

As swimmers increased their hand force, they swam faster. Swimmers with higher hand force values swam faster than swimmers with lower values. There was a quadratic relationship between hand force and swimming velocity. Technique analysis and instruction must be directed at increasing force throughout the entire stroke cycle.

Havriluk, R. (2004). Hand force and swimming velocity. In 15^th FINA World Sports Medicine Congress. Indianapolis.

Swimming technique and velocity improve rapidly with a comprehensive program of analysis and instruction.

The results demonstrate that even a relatively short duration of carefully targeted instruction can make a meaningful improvement in technique (as measured by the active drag coefficient) and performance (as measured by swimming velocity). A complete program includes force and video analysis, visual and kinesthetic cue instruction, practice at a slow enough speed to allow control, and individual feedback.

Havriluk, R. (2006). Magnitude of the effect of an instructional intervention on swimming technique and performance. In J. P. Vilas-Boas, F. Alves, A. Marques (Eds.), Biomechanics and Medicine in Swimming X. Portuguese Journal of Sport Sciences, 6(Suppl. 2), 218-220.

Anterior-posterior muscular imbalances in swimmers are substantial.

A training regimen that strengthens the arm abductors may not only decrease the incidence of injuries in all four strokes, but also increase hand force and, therefore, improve performance in backstroke.

Becker, T., & Havriluk, R. (2006). Bilateral and anterior-posterior muscular imbalances in swimmers. In J. P. Vilas-Boas, F. Alves, A. Marques (Eds.), Biomechanics and Medicine in Swimming X. Portuguese Journal of Sport Sciences, 6(Suppl. 2), 327-328.

Hand force analysis reveals limiting factors in the fastest swimmers.

An analysis of the pattern of application of hand force can reveal bilateral differences, force losses, and wasted motion. These factors were found on even the world’s fastest swimmers. Synchronized underwater video and hand force data shows the changes in arm motion necessary to swim faster.

Havriluk, R. (1998). Hand force analysis in swimming. Invited presentation at II Encontro de Tecnicos de Esportes Aquaticos, Rio de Janiero, Brazil, August.

Havriluk, R. (2006). Analyzing hand force in swimming: three typical limiting factors. American Swimming Magazine, 2006(3), 14-18.

Bilateral symmetry in hand force helps to maximize propulsion and minimize resistance.

A synchronized underwater video and force analysis is necessary to quantify asymmetries. The use of visual and kinesthetic cues can help swimmers minimize these differences. Improving bilateral symmetry in hand force will improve performance.

Havriluk, R. (2007). Analyzing hand force in swimming: Bilateral symmetry. American Swimming Magazine. 2007(1), 34-38.

Technique analysis and instruction improves performance far more than swimsuit design.

One week of a comprehensive program of technique analysis and instruction had an effect on the active drag coefficient that was 3.5 times as great as the effect from wearing a Fastskin®. While swimsuit design may make an immediate but minimal improvement, technique adjustments produce much greater though more gradual gains.

Havriluk, R. (2007). Improving performance in swimming: Swimsuit and technique resistance factors. Swimming in Australia, 24(1), 22-23.

Technology and strategies expedite skill learning.

An evaluation of swimmers’ skill level (basic, intermediate, or advanced) makes the appropriate technology more evident. Complementary strategies expedite the learning process - an optimal biomechanical model; visual and kinesthetic cues that complement the model; synchronized underwater video and force analysis; short swims at a slow speed with limited breathing; drills that isolate key technique elements; reminders before a swim and feedback immediately after.

Havriluk, R. (2008). Improving performance in swimming: Technology and learning strategies. Swimming World Magazine, 49(3), 37-38.

Breaststroke pullout is faster with a dolphin kick.

A dolphin kick during a breaststroke pullout provides a significant advantage over the traditional no-dolphin kick pullout.  The advantage comes from enhanced propulsion from the kick but not the pull.

McLean, S.P., Havriluk^, R., & Brandt, S. (2008). Effect of adding a dolphin kick to a breaststroke pullout. Medicine and Science in Sports and Exercise, in press.

Summary

Research supports Aquanex as a dependable method for analyzing swimming and aquatic therapy. The studies also show that technique is related to swimming velocity and that technique improvements will make swimmers go faster. It is important for swimmers continue to receive an adequate amount of technique analysis and instruction as they progress through the teenage years. A complete instructional program includes force and video analysis, visual and kinesthetic cues, practice at a slow enough speed to allow control, and individual feedback. Complementary strength training must target muscles used to exert force on the water and muscles that keep a swimmer structurally balanced.

Related Research

Havriluk, R. (2007). Variability in measurement of swimming forces: A meta-analysis of passive and active drag. Research Quarterly for Exercise and Sport, 78(2), 32-39.

Havriluk, R. (2005). Performance level differences in swimming: A meta-analysis of passive drag force. Research Quarterly for Exercise and Sport, 76(2), 112-118.