Abstract
e aim of this study was to examine the effects of concurrent dryland and sprint swimming interval training (SIT), and of SIT only, on swimmers’ performance and biomechanical variables before, during, and following 6 weeks of training. Twenty-four swimmers (age: 16.5±2.9 years) were as- signed to three groups of equal performance level and applied concurrent dryland and SIT three times per week, as follows: (i) maximum strength (three sets×four repetitions, load 90% of one-repetition maximum) [1RM]) prior to SIT (group: G-MS); (ii) muscular endurance (2 sets×20 repetitions , load 55% of 1RM) prior to SIT (group: G-ME); and (iii) SIT only (consisting of 2 series of 4×50 m sprints (group: G-CON)). Performance time, stroke rate (SR), stroke length (SL), and stroke index (SI) were measured during 4×50 m sprints. For pre- vs. post-performance time, SR, SL, and SI were similar between groups (p> 0.05). SR increased in G-MS and G-ME in week 6 vs. week 1 (p= 0.02), while SL and SI were similar between groups (p> 0.05). Concurrent dryland compared with sprint interval swimming training on the same day may progressively increase SR within a 6-week period, and all types of training
time, SR, SL, and SI were similar between groups (p> 0.05). SR increased in G-MS and G-ME in week 6 vs. week 1 (p= 0.02), while SL and SI were similar between groups (p> 0.05). Concurrent dryland compared with sprint interval swimming training on the same day may progressively increase SR within a 6-week period, and all types of training improved front crawl efficiency following a mesocycle of training. Keywords:dryland maximum strength; dryland muscular endurance; sprint swimming training; biomechanical variables 1. Introduction Competitive swimmers may apply maximum strength (3–5 sets, 3–5 repetitions, >85% of one-repetition maximum [1RM]) or muscular endurance in dryland training (2–4 sets, >12 repetitions, 40–60% of 1RM) prior to swimming training [1,2]. Following dryland training, the swimmers participate in swimming training to improve endurance [3] or sprint interval swimming training (SIT) with maximum effort to improve anaerobic potential [4–6]. Within a training microcycle, coaches may plan more than two dryland strength training sessions prior to in-water training, and this is regularly repeated during a mesocycle or longer periods of training [7]. There is evidence that the long-term concurrent application of dryland strength and endurance swimming training may improve performance compared with swimming training only, and this has been extensively reviewed and supported with experimen- talfindings [2,8–10] . However, no study in swimming has examined the possible effects of concurrent dryland maximum strength or muscular endurance training and SIT on swimmers’ performance. On the contrary, it has been well documented that a long-term application of SIT only may improve swimmers’ performance in race distances ranging from 50 to 400 m [11–13]. In addition, alterations in biomechanical variables such as stroke rate (SR), stroke length (SL), and stroke index (SI) may explain swimming performance [14]. However, Appl. Sci.2024,14, 2403.
Appl. Sci.2024,14, 2403 2 of 15 controversial findings have been reported for biomechanical variables from a combination of dryland training (80–90% of maximal load) with endurance training [10,15,16]. Pre- vious findings indicated increments in SR and SL after 4 weeks [16] but not after 6 to 12 weeks [10,15] . However, high-intensity swimming training applied during 4 weeks of intervention increased SR during maximal efforts of the 100 and 400 m front crawl [17]. It is possible that the biomechanical alterations observed during a training period depend on the swimmers’ level as well as the characteristics of the training [18,19]. To our knowledge, no study in swimming has examined the effects of concurrent dryland maximum strength or muscular endurance training and SIT applied on the same day on SR, SL, and SI during and after a training period. In addition, there is limited information available concerning the progression of swimmers’ SR, SL, and SI during a training period when different concurrent training plans have been applied. The aim of this study was to examine the effects of concurrent dryland maximum strength and SIT, as well as muscular endurance and SIT, and SIT only, on swimmers’ performance and biome- chanical variables before, during, and following 6 weeks of training. We hypothesized that swimmers will improve their performance and biomechanical characteristics irrespective of the training combination. 2. Materials and Methods 2.1. Participants Twenty-four national-level competitive swimmers (twelve males and twelve females) volunteered to participate in this study. All swimmers had participated in the national championship of the previous year. As inclusion criteria, each swimmer needed to meet the following: (i) be free from injury; (ii) indicate no use of medication prior to or during the training period; (iii) have at least 5 years of experience in competitive swimming; and (iv) participate in six swimming training sessions and two to three dryland sessions per week. After a thorough explanation of this study’s procedures, all swimmers or their legal guardians signed a consent form accepting their participation in this study. The local institutional review board approved the experimental protocol (approved number: 1111), which was
years of experience in competitive swimming; and (iv) participate in six swimming training sessions and two to three dryland sessions per week. After a thorough explanation of this study’s procedures, all swimmers or their legal guardians signed a consent form accepting their participation in this study. The local institutional review board approved the experimental protocol (approved number: 1111), which was according to the Helsinki Declaration. 2.2. Study Design A 3-group repeated-measure design was applied with pre-training and post-training period measurements. Following baseline testing, swimmers were divided into three groups of equal performance levels according to their 100 m swimming performance, and then completed a 6-week training mesocycle. Swimmers’ characteristics in each group are shown in Table. Table 1.Anthropometric and performance characteristics of the participants in each group. Variables G-MS (n = 8) G-ME (n = 8) G-CON (n = 8) Age (years) 17.0 ±2.6 15.9 ±2.0 16.7 ±4.2 Body mass (kg) 60.8 ±8.0 59.4 ±8.5 60.3 ±12.5 Body height (cm) 170.1 ±5.3 171.0 ±8.2 168.5 ±12.1 Body fat (%) 15.5 ±4.5 15.3 ±3.4 17.6 ±3.6 Body mass index (kg·m −2 ) 20.9 ±1.9 20.3 ±1.9 20.8 ±2.1 100 m front crawl performance time (s) 64.9±7.4 66.3 ±6.8 67.3 ±7.7 WA points (100 m front crawl) 457.5 ±95.8 425.0±75.6 411.8 ±104.9 Competitive training experience (years) 8.0±1.5 7.9 ±1.4 7.6 ±1.7 WA: World Aquatics, G-MS: group of maximum strength, G-ME: group of muscular endurance, G-CON: con- trol group. During the 6-week period, swimmers of the G-MS group (n = 8) performed a maximum strength dryland training session prior to SIT. Swimmers in the G-ME group (n = 8) performed a muscular endurance dryland training session prior to SIT, while G-CON (n = 8) performed the SIT only. All groups applied the concurrent session three times
Appl. Sci.2024,14, 2403 3 of 15 per week and 20 min after the dryland session. G-CON performed easy stretching and arm-swing exercises prior to SIT during the intervention days and no dryland training was applied within the mesocycle of intervention. All the swimming training sessions were the same for all groups. Measurements were conducted during the specific preparation period of the second seasonal cycle of the year-round training plan. All tests as well as training sessions were completed at the same time of the day (17:00 to 19:00 p.m.) in a 50 m outdoor swimming pool with a water temperature of 27 ◦ C. Ambient temperature during testing ranged between 20 and 25 ◦ C. All SIT testing procedures during, as well as prior to and post the 6-week period were carried out by experienced and certified personnel. The experimental design of the study is shown in Figure.Appl. Sci. 2024, 14, x FOR PEER REVIEW 3 of 15 During the 6-week period, swimmers of the G-MS group (n = 8) performed a maxi- mum strength dryland training session prior to SIT. Swimmers in the G-ME group (n = 8) performed a muscular endurance dryland training session prior to SIT, while G-CON (n = 8) performed the SIT only. All groups applied the concurrent session three times per week and 20 min after the dryland session. G-CON performed easy stretching and arm- swing exercises prior to SIT during the intervention days and no dryland training was applied within the mesocycle of intervention. All the swimming training sessions were the same for all groups. Measurements were conducted during the specific preparation period of the second seasonal cycle of the year-round training plan. All tests as well as training sessions were completed at the same time of the day (17:00 to 19:00 p.m.) in a 50 m outdoor swimming pool with a water temperature of 27 °C. Ambient temperature dur- ing testing ranged between 20 and 25 °C. All SIT testing procedures during, as well as prior to and post the 6-week period were carried out by experienced and certified person- nel. The
the same time of the day (17:00 to 19:00 p.m.) in a 50 m outdoor swimming pool with a water temperature of 27 °C. Ambient temperature dur- ing testing ranged between 20 and 25 °C. All SIT testing procedures during, as well as prior to and post the 6-week period were carried out by experienced and certified person- nel. The experimental design of the study is shown in Figure 1. Figure 1. Experimental design of the study: 1RM: one-repetition maximum; SR: stroke rate; SL: stroke length; SI: stroke index. 2.3. Testing Procedures All swimmers were evaluated before (pre) and after (post) the 6-week training period. On day 1, body mass and body height (Seca, Hamburg, Germany) were measured and body mass index was calculated. Body fat percentage was estimated according to Jackson and Pollock’s method [20] and lean body mass (LBM) was calculated according to Boer’s method [21]. On day 2, the swimmers performed 200 and 400 m front crawl tests, applying maximum effort. The recovery period between 200 and 400 m was 30 min, including a 5 to 10 min period of active recovery. From the two timed distances (200 and 400 m), the linear relationship of time vs. distance was drawn and the critical speed (CS) was determined as the slope of the regression line [3]. On day 3, the swimmers completed four repetitions of 50 m front crawl sprints (4 × 50 m) using a push-off start from within the water and starting every 2 min. The mean swimming performance time was used for the statistical analysis. Moreover, swimming time of each repetition was used to calculate the decrement score (DS) [22]. On day 4, performance time in a 100 m front crawl test with maximum effort was Figure 1.Experimental design of the study: 1RM: one-repetition maximum; SR: stroke rate; SL: stroke length; SI: stroke index. 2.3. Testing Procedures All swimmers were evaluated before (pre) and after (post) the 6-week training period. On day 1, body mass and body height (Seca, Hamburg, Germany) were measured and body mass index was calculated. Body fat percentage was estimated according
was Figure 1.Experimental design of the study: 1RM: one-repetition maximum; SR: stroke rate; SL: stroke length; SI: stroke index. 2.3. Testing Procedures All swimmers were evaluated before (pre) and after (post) the 6-week training period. On day 1, body mass and body height (Seca, Hamburg, Germany) were measured and body mass index was calculated. Body fat percentage was estimated according to Jackson and Pollock’s method [20] and lean body mass (LBM) was calculated according to Boer’s method [21]. On day 2, the swimmers performed 200 and 400 m front crawl tests, applying maximum effort. The recovery period between 200 and 400 m was 30 min, including a 5 to 10 min period of active recovery. From the two timed distances (200 and 400 m), the linear relationship of time vs. distance was drawn and the critical speed (CS) was determined as the slope of the regression line [3]. On day 3, the swimmers completed four repetitions of 50 m front crawl sprints (4×50 m) using a push-off start from within the water and starting every 2 min. The mean swimming performance time was used for the statistical analysis. Moreover, swimming time of each repetition was used to calculate the decrement score (DS) [22]. On day 4, performance time in a 100 m front crawl test with maximum effort was recorded. In all testing sessions, the SR was calculated by the time to complete 3 stroke cycles, and SL was calculated by the ratio of swimming speed to SR. SI was calculated by the product of SL and swimming speed. All biomechanical variables were measured at every 50 m during the 4×50 m sprints and the 100 m test and were averaged to obtain one value for each test, which was used for the statistical analysis. On day 5, the individual 1RM was evaluated in bench press (ICC = 0.99), seated pulley rowing (swimmers were allowed to move their torso during the pull; ICC = 0.98), and half squat exercises (knee
used for the statistical analysis. On day 5, the individual 1RM was evaluated in bench press (ICC = 0.99), seated pulley rowing (swimmers were allowed to move their torso during the pull; ICC = 0.98), and half squat exercises (knee
Appl. Sci.2024,14, 2403 4 of 15 angle 90 ◦ ; ICC = 0.99) using standard procedures [23]. Prior to each swimming testing procedure, the swimmers performed an 800 m standardized warm-up (400 m slow front crawl swimming, 4×50 m front crawl drills, and 4×50 m front crawl swimming with progressively increasing speed). 2.4. Training Content and Testing Both maximum strength and muscular endurance dryland sessions consisted of sit-ups and back extension exercises (3 sets×15 repetitions and 30 s resting interval) and three resistance training exercises that have been previously included in dryland sessions for competitive swimmers [15]. The dryland sessions’ characteristics are shown in Figure. The training volume of both dryland sessions were equalized by manipulating the number of sets, repetitions, load/intensity, and movement tempo as it is shown in Equation (1) [24]: Trainingvolume=Sets×Repetitions×%1RM×MT (1) where %1RM (repetition maximum) is the training load/intensity and MT is the movement tempo during a repetition in bench press, seated pulley rowing, or half squat.Appl. Sci. 2024, 14, x FOR PEER REVIEW 4 of 15 recorded. In all testing sessions, the SR was calculated by the time to complete 3 stroke cycles, and SL was calculated by the ratio of swimming speed to SR. SI was calculated by the product of SL and swimming speed. All biomechanical variables were measured at every 50 m during the 4 × 50 m sprints and the 100 m test and were averaged to obtain one value for each test, which was used for the statistical analysis. On day 5, the individual 1RM was evaluated in bench press (ICC = 0.99), seated pulley rowing (swimmers were allowed to move their torso during the pull; ICC = 0.98), and half squat exercises (knee angle 90°; ICC = 0.99) using standard procedures [23]. Prior to each swimming testing procedure, the swimmers performed an 800 m standardized warm-up (400 m slow front crawl swimming, 4 × 50 m front crawl drills, and 4 × 50 m front crawl swimming with progressively increasing speed). 2.4. Training Content and Testing Both maximum strength and muscular endurance dryland sessions consisted of sit- ups and
standard procedures [23]. Prior to each swimming testing procedure, the swimmers performed an 800 m standardized warm-up (400 m slow front crawl swimming, 4 × 50 m front crawl drills, and 4 × 50 m front crawl swimming with progressively increasing speed). 2.4. Training Content and Testing Both maximum strength and muscular endurance dryland sessions consisted of sit- ups and back extension exercises (3 sets × 15 repetitions and 30 s resting interval) and three resistance training exercises that have been previously included in dryland sessions for competitive swimmers [15]. The dryland sessions’ characteristics are shown in Figure 2. The training volume of both dryland sessions were equalized by manipulating the number of sets, repetitions, load/intensity, and movement tempo as it is shown in Equation (1) [24]: Training volume L Sets H Repetitions H %1RM H MT (1) where %1RM (repetition maximum) is the training load/intensity and MT is the movement tempo during a repetition in bench press, seated pulley rowing, or half squat. Figure 2. A graphic representation of the maximum strength and muscular endurance dryland train- ing sessions applied by the swimmers in the group of maximum strength (G-MS) and in the group of muscular endurance (G-ME) prior to sprint swimming training during the 6-week training pe- riod; 1RM: one-repetition maximum. 2.5. Sprint Swimming Interval Training and Decrement Score The SIT session was the same in all experimental groups and it was applied after an 800 m standardized warm-up (400 m slow front crawl swimming, 4 × 50 m front crawl drills, and 4 × 50 m front crawl swimming with progressively increasing speed), including Figure 2.A graphic representation of the maximum strength and muscular endurance dryland training sessions applied by the swimmers in the group of maximum strength (G-MS) and in the group of muscular endurance (G-ME) prior to sprint swimming training during the 6-week training period; 1RM: one-repetition maximum. 2.5. Sprint Swimming Interval Training and Decrement Score The SIT session was the same in all experimental groups and it was applied after an 800 m standardized warm-up (400 m slow front crawl swimming, 4×50 m front
strength (G-MS) and in the group of muscular endurance (G-ME) prior to sprint swimming training during the 6-week training period; 1RM: one-repetition maximum. 2.5. Sprint Swimming Interval Training and Decrement Score The SIT session was the same in all experimental groups and it was applied after an 800 m standardized warm-up (400 m slow front crawl swimming, 4×50 m front crawl drills, and 4×50 m front crawl swimming with progressively increasing speed), including two sets of 4 repetitions for 50 m sprints. The first set was performed in front crawl and the second set in the personally preferred swimming stroke. Both sets were applied using a push-off start and starting every 2 min. A five-minute passive resting interval was allowed between the two sets. The daily training volume during the days when SIT applied, was 3000 m and the swimming training during the remaining 3 days of the week ranged from 3200 to 5000 m. The training intensity was adjusted according to CS and applied in three training zones: (i) zone 1 corresponding to 95–97% of CS, (ii) zone 2 corresponding to 99–101% of CS, and (iii) zone 3 corresponding to 104–107% of CS [3]. Performance time of the first 4×50 m front crawl training set in the first SIT session of each week was recorded
Appl. Sci.2024,14, 2403 5 of 15 by experienced timekeepers and the mean time as well as the calculated DS were used for the statistical analysis. Moreover, the SR, SL, and SI were calculated during the first set of 4×50 m sprints and the mean values from each set in each week were used for the statistical analysis. The internal training load of daily swimming training was estimated by calculating the session rating of perceived exertions (session-RPE) and using a 10-point Borg scale [25]. The swimming training volume was recorded daily and was stored for subsequent analysis. 2.6. Statistical Analysis Normal distribution of the data was tested using Kolmogorov–Smirnov test and sphericity was verified using a Mauchly test. When the assumption of sphericity was not met, the significance ofFratios was adjusted according to the Greenhouse–Geisser correction. Analysis of variance on repeated measures in two factors (3 groups×time points) was used for all dependent variables (anthropometric characteristics, performance time in the 4×50 m, 100 m, SR, SL, SI, and 1RM). A Tukey honest significant difference as a post hoc test was used to compare the means when significant F ratios were found. In addition, analysis of variance in two factors (3 groups×repeated measures) was used for all dependent variables as well as training volume and training load during the 6-week training period. The∆values were estimated from post- to pre-measurements and from week 6 to week 1 for the performance time, the SR, SL, and SI. Furthermore, one-way analysis of variance between groups was used for percentage differences (%∆). To estimate the size of the main effects and interaction, the partial eta-squared (ηp 2) values from the analysis of variance were used. Theηp 2was considered small if the value was≤0.01, medium if it was≤0.06, and large if it was≥0.14. Theηp 2for the sample size in the present study (n = 24) separated by three equal groups with sample (n = 8) resulted in a power of analysis corresponding to 0.71 [26]. Pearson correlation was used to examine relationships between variables and was qualitatively interpretated as small (r= 0.1–0.3), moderate (r= 0.3–0.5), large (r=
Description
This study investigates the impact of combined dryland and swimming training on performance metrics in competitive swimmers.