Assessment of individual anaerobic threshold and stroking parameters in swimmers aged 10–11 years

Abstract

The assessment of blood lactate concentration is considered essential for the physiological diagnosis of swimming performance. But for a more detailed and complete analysis of a swimmer's strengths and weaknesses, it is also important to examine his or her technical characteristics. However, few studies have combined physiological and technical evaluation in child swimmers. The aim of the present study was to assess the metabolic anaerobic threshold (blood lactate concentration and corresponding swimming velocity) of 10-to 11-year-old swimmers (n015) using an individualized intermittent incremental protocol. Comparison was made with the traditionally used 4 mmol × l (1 lactate threshold. In addition, stroke rate, stroke length, and stroke index were measured throughout the experimental protocol for assessment of the anaerobic threshold. Each swimmer performed a front crawl 5 )200 m test, in which the swimming velocity was controlled by an acoustic signal each 50 m. Blood samples were collected from the ear lobe (Lactate Pro, Arkay, Inc., Kyoto, Japan), at rest and after each step. Stroke rate was registered by a Seiko base 3 chronofrequencemeter; stroke length, stroke index, and velocity were calculated at the end of each 200 m. The individual anaerobic threshold occurred at 2.3 mmol × l (1 (s 00.59), and the corresponding velocity was 1.026 m × s (1 (s 00.053), much lower than the traditionally used 4 mmol × l (1 value (or even 3.5 mmol × l (1 ). The velocity corresponding to 4 mmol × l (1 and 3.5 mmol × l (1 was 1.081 m × s (1 (s 00.056) and 1.067 m × s (1 (s00.055), respectively. Stroke rate increased and stroke length decreased throughout the incremental protocol (i.e. with increasing velocity). The stroke index showed a tendency to increase throughout the protocol, with a significant difference from the first to the second step. The velocity corresponding to 4 mmol × l (1 (and 3.5 mmol × l (1 ) does not represent the metabolic individual anaerobic threshold in trained swimmers, independently of their age, and agegroup swimmers prefer to increase their velocity through an increase in stroke rate. Thus, given the importance of developing swimming technique in age-group swimmers, coaches should implement the lengthening of swimmers' stroke cycles in their training practice routines, so that they limit the effects of reduced stroke length when velocity increases.

The Effectiveness of Primary Teaching Swimming Programme for 6–7 Year-old Children

“…Vieni iš sudėtingiausių pradinių plaukimo mokymo įgūdžių yra pratimai, kurie apima kojų darbą plaukiant krauliu krūtine ir nugara bei rankų darbą plaukiant krauliu krūtine ir nugara sulaikant kvėpavimą. Reaktyviniai įgūdžiai yra labai svarbūs norint toliau sėkmingai mokyti plaukimo būdų technikos (Fernandes et al, 2010). Išmokus plaukti krauliu sulaikius kvėpavimą galima pradėti mokytis įkvėpimo technikos plaukiant krauliu ir kvėpavimo kontrolės plaukiant krauliu nugara (Forbes, 2008).…”

Is the Critical Velocity Test a Good Tool For Aerobic Assessment of Children Swimmers?

“…One week before the competition, each participant performed a 5 x 200 m front crawl intermittent incremental protocol for individual anaerobic threshold assessment, with 30 s intervals and 0.05 m/s increments between steps, as described in deeper detail by Fernandes et al [6]. A standardized warm-up of 600 m, consisting primarily of aerobic swimming of low to moderate intensity, was conducted before the test protocol.…”

“…At this moment of a swimmer's career, practitioners are in the ''basic training'' phase, developing simultaneously the proper starting, swimming, and turning techniques, as well as their basic conditional skills (namely their aerobic capacity) to prepare for future intense high-volume training [4]. Although existing several differences between the physiological responses of children and adults to exercise [5], children swimmers are rarely involved in training control, and the investigation in these ages is very low comparing to that conducted with adult swimmers [6]; this seems to be due to financial limitations, but also to ethical *Address correspondence to this author at Rua Dr. Plácido Costa, 91 4200-450, Porto, Portugal; Tel: +351 225074763; E-mail: smarisacsousa@hotmail.com issues [7]. The almost inexistence of swimmers evaluation and training control at young ages could lead to inadequate volume and prescription of training intensities, essentially based on coaches' previous experience [8], not considering the swimmers specific training responses [5,9].…”

“…To evaluate the swimmer's aerobic performance one of the most valid indicators is the individual anaerobic threshold, as it gives important information regarding the level of development of the swimmer's aerobic capacity [4,6,[14][15][16], being very useful to establish the aerobic training intensities in swimming. However, despite the existence of several tests to assess the velocity corresponding to the anaerobic threshold, some imply the use of invasive techniques based in expensive procedures of blood collection for lactate concentration analysis, and, frequently, are also very time consumable [10].…”

The Physiological Responses to 5000 m Open Water Swimming Exercise in Children

“…Before testing, a 600 m standardized warmup protocol was used. 29 The HR of each athlete at each level was measured telemetrically via a Polar S810i (Polar Electro, OY, Finland) HR recorder. Moreover, blood samples were taken from the fingertip into heparinized capillary hematocrit tubes after every 400 m of swimming.…”