Intracycle velocity variation is a swimming relevant research topic, focusing on understanding the interaction between hydrodynamic propulsive and drag forces. We have performed a systematic scoping review to map the main concepts, sources and types of evidence accomplished. Searches were conducted in the PubMed, Scopus and Web of Science databases, as well as the Biomechanics and Medicine in Swimming Symposia Proceedings Book, with manual searches, snowballing citation tracking, and external experts consultation. The eligibility criteria included competitive swimmers’ intracycle velocity variation assessment of any sex, distance, pace, swimming technique and protocol. Studies’ characteristics were summarized and expressed in an evidence gap map, and the risk of bias was judged using RoBANS. A total of 76 studies, corresponding to 68 trials involving 1440 swimmers (55.2 and 34.1% males and females), were included, with only 20 (29.4%) presenting an overall low risk of bias. The front crawl was the most studied swimming technique and intracycle velocity variation was assessed and quantified in several ways, leading to extremely divergent results. Researchers related intracycle velocity variation to coordination, energy cost, fatigue, technical proficiency, velocity, swimming techniques variants and force. Future studies should focus on studying backstroke, breaststroke and butterfly at high intensities, in young, youth and world-class swimmers, as well as in IVV quantification.

Intra- and inter-cycle velocity variations are of utmost importance for achieving enhanced swimming performances. However, intra-cycle events can impact and interfere with the subsequent cycles, making relevant to study several consecutive cycles allowing a better understanding of this possibility. We have assessed front crawl intra- and inter-cyclic velocity variations and overall biomechanical variables in sprint front crawl swimming. Twenty-seven elite swimmers performed 25 m all-out front crawl, were videotaped using moving cameras placed at the sagittal plane and were grouped according to their sprint mean velocity. Coefficient of variation, root mean square error and mean velocity differences between two consecutive paired cycles allowed assessing intra- and inter-cycle velocity variations. Visual inspection was performed to analyse possible variability causes and independent-measures t-test allowed comparing groups. Sprint front crawl was characterised by intra- (11.12 ± 2.98) and inter-cycle velocity variation (2.27 ± 0.80 of inter-cycle velocity coefficient of variation and 0.031 ± 0.014 of root mean square error), with no differences between fastest and slowest swimmers. Front crawl intra-cycle velocity variation was not related to mean velocity and cycle sequence but considered swimmers’ personal strategy. Despite some abnormal oscillations within cycles, inter-cycle velocity variation was not caused by intra-cycle velocity variation, mean velocity or cycle sequence.

Tennis is an asymmetric sport characterized by a systematic repetition of specific movements that may cause disturbances in muscular strength, power, and torque. Thus, we assessed (i) the torque, power, ratio production, and bilateral asymmetries in the shoulder’s external and internal rotations at 90 and 180°/s angular velocities, and (ii) the point duration influence of the above-mentioned variables. Twenty competitive tennis players performed external and internal shoulder rotations; an isokinetic evaluation was conducted of the dominant and non-dominant upper limbs before and after five and ten forehands. A higher torque production in the shoulder’s internal rotations at 90 and 180°/s was observed for the dominant vs. non-dominant sides (e.g., 63.1 ± 15.6 vs. 45.9 ± 9.8% and 62.5 ± 17.3 vs. 44.0 ± 12.6% of peak torque/body mass, p < 0.05). The peak torque decreased only after ten forehands (38.3 ± 15.8 vs. 38.2 ± 15.8 and 39.3 ± 16.1 vs. 38.1 ± 15.6 Nm, respectively, p < 0.05), but without impacting speed or accuracy. Unilateral systematic actions of tennis players caused contralateral asymmetries, evidencing the importance of implementing compensatory training. The forehand kinematic assessment suggests that racket and wrist amplitude, as well as speed, are important success determinants in tennis.

Backstroke swimming, a cyclic and continuous movement, displays a repeating structure due to the repeated action of the limb, presenting similar (but not identical) cycles. Some variability is generated by instabilities, but this may play a functional role in the human performance, allowing individual adaptations to constraints. The current study examined the role of velocity variability in backstroke performance, hypothesizing that this variable is associated with swimmers’ performance. Sixteen elite and fifteen good-level swimmers were video recorded in the sagittal plane when performing 25 m backstroke at maximal intensity in order to determine hip velocity and mean velocity, stroke rate, stroke length and indexes of coordination/synchronization. Lyapunov maximal exponent and sample entropy were also calculated for successive cycles. The elite swimmers’ performances were more unstable (0.1742 ± 0.1131 versus 0.0831 ± 0.0042, p < 0.001) and complex (0.9222 ± 0.4559 versus 0.3821 ± 0.3096, p < 0.001) than their good-level counterparts, but intracycle velocity variation did not differ (11.98 ± 3.47 versus 12.03 ± 3.16%, p > 0.05). Direct relationships were observed between mean velocity and stability (r = 0.40, p = 0.03), as well as with complexity (r = 0.53, p = 0.002), with intracycle velocity variation and complexity also being related (r = 0.38, p = 0.04). Backstroke performance is associated with velocity variability, with elite swimmers being able to control it through several adaptations, overcoming the high drag and inertia.

We characterized the physical and physiological profiles of high-level female Portuguese handball players and examined the relationships between their anthropometric characteristics, general motor performance and cardiopulmonary fitness. Twenty-four high-level female handball players with an average age of 23.6 ± 5.5 years, height of 173.6 ± 5.1 cm and body mass of 72.6 ± 9.1 kg volunteered to participate. A Pearson correlation test was used to assess the relationship between variables. Direct relationships were observed between the players’ height and arm span (r = 0.741), as well as between their squat jump and countermovement jump performances with regard to body mass (r = 0.448 and 0.496, respectively). The 9 m jump shot has a large relationship with the 7 m standing throw (r = 0.786) and between left hand dynamometry and body mass index (r = 0.595). The 30 m sprint has a relationship with the 7 m standing throw (r = −0.526) and the 9 m jump throw (r = −0.551). Oxygen uptake has a relationship with the players’ height (r = −0.482) and time limit (r = 0.513), while the fitness index has a relation to the players’ height (r = −0.488) and arm span (r = −0.422). Our results should be considered when using physical testing to plan optimal physical training regimens in elite team handball.

Breaststroke and butterfly are complex swimming techniques requiring refined motor skills to perform successfully, with coordinated and consistent interaction between propulsive and resistive forces being decisive when considering swimmers expertise. The current study analysed those techniques intercycle kinematic variation in two swimmers cohorts. Twenty elite and 15 national level swimmers performed one 25 m breaststroke and one 25 m butterfly sprints, with an underwater camera recording images at 120 Hz in the sagittal plane. Mean velocity, maximum and minimum velocities, stroke rate and length, intracycle velocity variation and phases relative duration were calculated for consecutive cycles (elite: five breaststroke/butterfly, national level: eight breaststroke/seven butterfly). The two highest peaks and the lower peak in between in breaststroke were also addressed. Intercycle and inter-groups analysis were performed using ANOVA, ANCOVA and Statistical Parametric Mapping. Elite and national level differed regarding breaststroke mean and maximum velocities, 1st and 2nd peaks and minimum between peaks (1.30 ± 0.02 vs 1.15 ± 0.02 m/s, 2.13 ± 0.05 vs 1.88 ± 0.06 m/s, 1.63 ± 0.05 vs 1.48 ± 0.05 m/s, 2.13 ± 0.05 vs 1.86 ± 0.05 m/s, 1.33 ± 0.04 vs 1.23 ± 0.04 m/s), and butterfly mean, maximum and minimum velocities, stroke rate and intracycle velocity variation, respectively (1.65 ± 0.01 vs 1.50 ± 0.01 m/s, 2.20 ± 0.04 vs 2.09 ± 0.04 m/s, 1.12 ± 0.04 vs 0.79 ± 0.04 m/s, (57.9 ± 0.9 vs 54.9 ± 1.0cycles/min, 18.4 ± 1.3 vs 23.7 ± 1.3 %). Elite and national level swimmers showed consistent breaststroke intercycle kinematic variation, but a butterfly mean velocity decay, with the upper limbs release and recovery, and the outsweep phases originating variability between butterfly cycles. Skill levels contrasted in technical and strategic features at sprint breaststroke and butterfly but showed similar velocity variability between consecutive swimming cycles.