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ObjectiveTo determine whether deep brain stimulation (DBS) causes swimming impairment, we systematically compared swimming ability between DBS on vs off in 18 patients.MethodsWe conducted a randomized blinded crossover study, comparing swimming ability between DBS on vs off, within participants. Participants swam 3 laps of front crawl and 3 laps of breaststroke. Prespecifed primary outcomes were proportion of lap completed, lap time, and Aquatic Skills Proficiency Assessment (ASPA) score. Prespecified secondary outcomes were a qualitative description of marked changes observed.ResultsEighteen participants with Parkinson disease (n = 13), essential tremor (n = 3), Tourette syndrome (n = 1), or posttraumatic brain injury proximal tremor (n = 1), treated with posterior subthalamic area (n = 15) or globus pallidus interna (n = 3) DBS were assessed. There was no significant effect of DBS on/off status on any outcome measure for front crawl or breaststroke. Three participants showed changes in both qualitative and quantitative assessments. Of these, 1 participant displayed reduction in swimming ability: impairment in all outcomes with DBS on, normalizing with DBS off (the same individual as previously reported). The participant displayed difficulty coordinating limb movement as well as postural control. Two participants showed improvements in lap time and ASPA scores with DBS on.ConclusionOverall DBS did not impair swimming performance, although 1 patient demonstrated a stimulation-induced drowning hazard. There were no anatomic or clinical features unique to the individual with swimming impairment. Patients should be warned about the possibility of DBS-induced drowning hazard and should swim with capable supervision after DBS.Classification of EvidenceThis study provides Class IV evidence that for patients with implanted DBS electrodes, the stimulation on condition, compared with stimulation off, did not significantly impair swimming performance. A formal assessment of unblinding would have been helpful.

This study examined the relationships between selected kinematic and physiological parameters and their influence on performance during incremental exercise in elite swimmers competing at the international level. Eleven men and ten women (all specialized in 200-m events) performed an incremental 7 x 200-m test in their specialized stroke. Stroke rate (SR), stroke length (SL), velocity (V), and blood lactate concentration (BLa) were measured for each 200 m. In addition to the cross-sectional group design, the longitudinal performance of a male swimmer was evaluated by 4 tests during a period of 20 weeks. Stroke rate increased and SL decreased with V, regardless of the age, stroke, or gender of the swimmer. Statistically significant correlations were found between SR and V (p < 0.01; r = 0.66 to 0.99), SR and SL (p < 0.01; r = -0.78 to -0.99), SL and V (except for women's freestyle and breaststroke) (p < 0.01; r = -0.67 to -0.98), and BLa and V (p < 0.01; r = 0.7 to 0.96). Changes in SR and SL were not affected by changes in BLa. Similar velocities were produced with different combinations of SR and SL. The fastest times reached in the test were generally slower than expected, and the performance in the test was not associated with competition performance. The case study revealed similar results to those of the group. The test used in this study was informative with respect to identifying the most economical and effective stroke kinematics combination for slow to submaximal velocities. It is possible that the swimming speeds were not maximal in the final 200-m swim because of cumulative fatigue, which is a major limitation for assessing race pace. An additional test that produces velocities similar to those used in competitions would be more useful for the purpose of providing optimal kinematic information specific to racing speeds, which would facilitate performance improvement through regular monitoring in training.

ROBERTS, B. S., K. S. KAMEL, C. E. HEDRICK, S. P. MCLEAN, and R. L. SHARP. Effect of a FastSkin TM Suit on Submaximal Freestyle Swimming. Med. Sci. Sports Exerc., Vol. 35, No. 3, pp. 519 –524, 2003. Purpose: Nine male collegiate swimmers swam three 183-m freestyle trials at “moderate, moderately hard, and hard” paces while wearing a traditional brief-style suit and on another occasion while wearing a newly designed suit covering the torso and legs with a material designed to reduce drag (FS). Methods: Postswim blood lactate concentration, V u O2, and rating of perceived exertion were measured. Average stroke length and rate, and breakout distance were determined for each swimming trial. Passive drag and buoyant force were also determined on swimmers while wearing both suits. Results: Swimmers swam at a higher mean velocity while wearing the FS (pooled mean % difference 2%), but this was accompanied by a significant increase in V u O2 (4% difference, P 0.05) and blood lactate concentration (10% difference, P 0.05). Comparison of physiological responses at standardized freestyle swimming speeds of 1.4 and 1.6 m·s 1 revealed no significant difference between the two suit conditions. Passive drag of the swimmers while being towed was not significantly different between the suits. Swimmers were significantly more buoyant while wearing the brief-style suit than the FS suit ( P 0.05). Conclusion: These findings provide no evidence of either physical or physiological benefits of wearing these suits during submaximal freestyle swimming. ompetitive swimming suits made from a proprietary fabric purported to reduce water resistance (active drag) and increase buoyancy were recently designed and are being worn by these athletes in hopes of improving performance. Although it is widely accepted that reducing active drag and increasing buoyancy will decrease the physiological cost of any given swimming speed (2–5,8 –18), currently only one study has investigated the drag characteristics of these swimsuits. Toussaint et al. (17) found no difference in active drag with the use of one of these body suits (FastSkin TM by Speedo ® ). However, this study provided no insight into the buoyant characteristics of these suits and, more importantly, examined no physiological variables as they related to the use of these suits. Trappe et al. (18) showed that wearing a neoprene wet suit significantly reduced both V u O2 and V u E during swimming at velocities ranging from 0.9 to 1.3 m·s 1 . Furthermore, the magnitude of this effect was positively related to the amount of body surface covered by the suits. Because neoprene is highly buoyant, part of the explanation for the reduced physiological demands of swimming is likely the added buoyancy provided by the wet suit. However, it is also possible that simply covering the skin might also reduce physiological cost by decreasing active drag independent from changes in buoyancy. Starling et al. (14) showed that wearing torso suits made from the same fabric as standard brief-style swimsuits reduced both V u O2 (by 4%) and blood lactate concentration (by 16%) while increasing distance per stroke (by 4%) during freestyle swimming at a standardized speed. These findings are consistent with the results of Sharp and Costill (12), who showed that shaving exposed body hair reduced the physiological cost of breaststroke swimming at a standardized speed. In this study V u O2 was reduced 9%, postswim blood lactate concentration was reduced 20%, and distance per stroke during the swim was increased 12%. Combined with the reduced velocity decay during a push-off and glide test, these results were attributed to a reduction in active drag after shaving exposed body hair. Collectively, the results of these studies suggest that successful attempts to either reduce active drag or increase the buoyancy of the swimmer will reduce physiological cost of swimming and increase distance per stroke. It was the purpose of the present study to examine the effects of wearing a FastSkin TM suit made from a putative dragreducing fabric on physiological and biomechanical responses to freestyle swimming.

The consistency of performance between events impacts how athletes should specialize in events, how competitions should be structured, and how changes in performance affect an athlete's placing in an event. We have therefore determined the consistency of swimming performance in events within and between two national-level competitions. We used mixed linear modeling to analyze official performance rimes of 149 male and 162 female swimmers at a junior national championship, and of 117 male and 104 female swimmers at an open national championship 20 d later. The events differed in stroke (backstroke, breaststroke, butterfly, freestyle, and individual medley) or distance (50-1500 m). Swimmers were most consistent in their performance for the same event between the two competitions (typical variation between competitions, 1.4%; 95% likely range of true value, 1.3-1.5%). They were less consistent between distances of a given stroke within each competition (1.7%; 1.5-1.9%) and least consistent between strokes for a given distance (2.7%; 2.3-3.1%). Variation in performance between the longest continuous freestyle distances (400, 800, and 1500 m) in the open competition was half that between widely spaced freestyle distances (50, 200, and 800 m). Faster swimmers were more consistent (1.1%; 0.9-1.4%) for the same event between competitions than slower swimmers (1.5%; 1.3-1.9%). The conclutions held that (a) Swimmers are stroke specialists rather than distance specialists; with the present set of events in competitions, they should concentrate training and competing on a particular stroke rather than a particular distance. (b) More swimmers would have a chance of winning a medal if events of a given stroke differed more widely in distance. (c) Factors that affect performance time by as little as 0.5% will affect the placing of a top junior swimmer.

Nine male collegiate swimmers (EXP) were studied 8 d before (PRE) and 1 d after (POST) shaving the hair from their arms, legs, and exposed trunk. A control group (CON, N = 4) of their teammates was also tested at these times but did not remove body hair. In PRE and POST, distance per stroke (SL), VO2, heart rate (HR), and post-swim blood lactate concentration (BL) were measured during a 365.8 m breaststroke swim at approximately 90% effort. Subjects also performed a tethered breaststroke swim with retarding forces of 6.27, 7.75, and 9.26 kg. The EXP group experienced a significant (P less than 0.05) reduction in BL (mean +/- SE: 8.48 +/- 0.78 to 6.74 +/- 0.74 mmol.l-1), a decreased VO2 (3.60 +/- 0.15 to 3.27 +/- 0.14 l.min-1), an increase in SL (2.07 +/- 0.08 to 2.31 +/- 0.10 m.stroke-1), and an insignificant (P = 0.08) decline in HR (174 +/- 5 to 168 +/- 4 beats.min-1) during the free swim. The CON group showed no changes in BL, SL, or HR. During the tethered swim, there were no significant PRE-POST differences in VO2, HR, or BL for either group. In a separate group of swimmers (nine who shaved body hair and nine controls), removing body hair significantly reduced the rate of velocity decay during a prone glide after a maximal underwater leg push-off. It is concluded that removing body hair reduces active drag, thereby decreasing the physiological cost of swimming.

CRAIG, A. B., JR. Breath holding during the turn in competitive swimming. Med. Sci. Sports Exerc., Vol. 18, No. 4, pp. 402–407, 1986. Breath holding times were measured during competition and averaged 5.0 sec in the breaststroke events, 4.3 sec in freestyle, 3.7 sec in butterfly, and 3.3 sec in backstroke. These times represented aproximately 30% of the total time of swimming breaststroke and freestyle races but only 20% of the time of backstroke and butterfly events. Pulmonary gas exchanges of O2 and CO2 were studied in eight male swimmers during the first turn after the start of a swim and during the third turn after continuous swimming. It was concluded that biomechanical considerations of optimizing a turn are in most circumstances not limited by the increased PCO2 and the decreased PO2 in the alveoli related to the brief period of breath holding. In turns which last longer than about 5.5 s, the swimmers may experience a strong urge to breathe. This “breaking point” sensation is brief and need not compromise the conclusion of a well-executed turn.

Swim records data from the U.S. Masters swim program afforded a chance to estimate the decline in swim performance over middle life. Men's records data indicated a falloff in swim performance of slightly less than one percent per year over the ages of 27.5 to 57.5 years. Men's decline in freestyle performance was seen to be essentially the same, regardless of varying oxygen requirements secondary to the distance swum. Men's decline in swim performance for the breaststroke and backstroke events was nearly that of the freestyle. Falloff in men's performance in the butterfly stroke rose to 1.47 percent per year. Women's times showed a decline between 20 to 50 percent greater than that seen for the men. Previous findings of athletes' decrease in pulmonary function over middle age closely parallel the observed decrease in Masters swimmers' records--approximately one percent per year. Language: en