Comparison of advanced and intermediate 200-m backstroke swimmers' dominant and non-dominant shoulder entry angles across various swimming speeds

Abstract

During backstroke, an optimum shoulder entry angle of 180° has been anecdotally suggested; however, this has yet to be investigated biomechanically. The aim of this study was to quantify shoulder entry angles for advanced and intermediate backstroke swimmers. Six advanced (season's best <150 s) and six intermediate (season's best >160 s) 200-m backstroke swimmers had markers applied to the medial humeral epicondyles and glenoid cavities. Following a familarization period, participants completed backstroke swimming trials (90 s each) in a swimming flume at 50%, 60%, 70%, and 80% of their season's best 200-m velocity. A camera positioned above the flume recorded frontal plane motion, which was digitized and analysed in Simi Motion Systems. The mean peak angle between the upper arm and the line of progression was established in ten strokes for each participant. The results showed backstroke shoulder entry angles for advanced swimmers (170°) were significantly closer to the suggested optimum 180° compared with those of intermediate swimmers (161°). The non-dominant arm displayed values closer to the optimum (171°), while swimming speed had no effect on backstroke shoulder entry angle. In conclusion, backstroke shoulder entry angle may help discriminate between advanced and intermediate backstroke swimmers and may be influenced by laterality dominance, being independent of swimming speed.

Velocity Variability and Performance in Backstroke in Elite and Good-Level Swimmers

“…Our elite swimmers move their upper limbs out of the water more rapidly and have a higher stroke rate, as observed in world-class backstrokers [ 23 ]. Moreover, a better body roll (allowing the hand to glide longer) and an extended second up sweep when finishing the cycle account for higher stroke lengths [ 13 , 34 ]. We observed that the elite swimmers upper limb coordination was more continuous, even if the catch up is the exclusive coordination mode for backstroke (due to the limited shoulder flexibility and the specific body roll [ 18 ]).…”

“…We observed that the elite swimmers upper limb coordination was more continuous, even if the catch up is the exclusive coordination mode for backstroke (due to the limited shoulder flexibility and the specific body roll [ 18 ]). Thus, swimmers should minimize their upper limb cycle lag time to compensate for the speed loss during the second up sweep [ 23 , 34 ]. Possible reductions in the shoulder entry angle from the suggested optimum may increase resistive drag due to the lateral deviations, but this can be reduced through improvements in technique [ 34 ].…”

“…Thus, swimmers should minimize their upper limb cycle lag time to compensate for the speed loss during the second up sweep [ 23 , 34 ]. Possible reductions in the shoulder entry angle from the suggested optimum may increase resistive drag due to the lateral deviations, but this can be reduced through improvements in technique [ 34 ]. In addition, the index of synchronization demonstrated that both groups maintained a constant pattern in their lower limb action at the same relative time in each backstroke cycle [ 19 ].…”

Hydrodynamic Flow Characteristics of a Recirculating Pool: Examining the Ecological Validity for Training and Testing

“…Furthermore, modern RSFs are typically multifeatured, including underwater treadmills and protruding steps for therapeutic use to improve the versatility of the RSF (25,34). These nonrectangular multifeatured RSFs have been used to assess metabolic work estimation (25,27) and upper-extremity movement (1,24). However, the effects these nonrectangular multifeatured RSFs have on hydrodynamic flow is currently unknown because studies using them have mostly relied on measurements from a single location distance from the projection channel (25,27,33).…”

Automated LED tracking to measure instantaneous velocities in swimming

“…In swimming practice, video recordings are used in a variety of ways. They are used for race analysis (software: SwimWatch, SwimOptimum), qualitative technique analysis and quantitative 2D or 3D analysis of kinematic parameters (software: Qualisis, Simi [10][11][12][13][14][15][16][17][18]) of strokes, starts and turns [19]. The use of markers (on body landmarks) is a useful addition to video analysis to obtain quantitative information.…”