The purpose of this study was to investigate the effect of combined linear and nonlinear periodic training on physical fitness and competition times in finswimmers. The linear resistance training model (6 days/week) and nonlinear underwater training (4 days/week) were applied to 12 finswimmers (age, 16.08± 1.44 yr; career, 3.78± 1.90 yr) for 12 weeks. Body composition measures included weight, body mass index (BMI), percent fat, and fat-free mass. Physical fitness measures included trunk flexion forward, trunk extension backward, sargent jump, 1-repetition-maximum (1 RM) squat, 1 RM dead lift, knee extension, knee flexion, trunk extension, trunk flexion, and competition times. Body composition and physical fitness were improved after the 12-week periodic training program. Weight, BMI, and percent fat were significantly decreased, and trunk flexion forward, trunk extension backward, sargent jump, 1 RM squat, 1 RM dead lift, and knee extension (right) were significantly increased. The 50- and 100-m times significantly decreased in all 12 athletes. After 12 weeks of training, all finswimmers who participated in this study improved their times in a public competition. These data indicate that combined linear and nonlinear periodic training enhanced the physical fitness and competition times in finswimmers.
Periodic training, one of the training methods to improve muscular function and athletic performance (
Periodic training can be either linear or nonlinear. Linear training is a traditional method that maximizes muscular strength and power and improves athletic performance by gradually modulating exercise intensity from low-intensity, high-volume training to high-intensity, low-volume training on a specific schedule (
However, results of previous research comparing linear with nonlinear periodic training have been inconsistent.
These inconsistent results were thought to be caused by various factors such as genetic differences between athletes and nonathletes, the exercise experiment used, and physiological adaptability (
It is especially thought that the duration of field and underwater training needs to be shortened in accordance with the athlete’s condition and training situation. Furthermore, additional specific training that can stabilize core muscles is required because finswimmers especially need lumbar muscular strength. Training programs also need to be adapted for the different events, that is, short-, middle-, and long-distance races. Consequently, the purpose of this study was to examine how combining both linear and nonlinear training affects body composition, physical strength related to athletic performance, and swimming times of high school short-distance finswimmers through linear periodic field training and nonlinear periodic underwater training that regulates the amount of training to suit the training purpose, the specific event, and the finswimmers’ environment. Our goal is to present an effective periodic training method for short-distance finswimmers.
The subjects were 12 elite high school finswimmers who had been swimming competitively for at least 3 yr. The participants were informed about the purpose of the experiment, the procedures, and the possible discomforts, risks, and benefits of the study before they signed a consent form. Data were collected before and after the training program. Subject characteristics are shown in
Weight (kg), fat free mass (kg), and percentage fat were measured using the Inbody 3.0 System (Biospace, Seoul, Korea). BMI was calculated as weight/height2 (kg/m2). Waist circumference was measured at the midpoint between the lower border of the rib cage and the iliac crest.
Physical fitness was measured by flexibility, agility, isotonic strength (1 rep max [1 RM]), and isokinetic strength. Flexibility was defined as mobility and suppleness of the lumbar area, as measured by the mean ranges of forward trunk flexion and backward trunk extension in the water (
The sargent jump test was used to measure the ability to start and turn in water, and it was measured using the TKK-5406 (Takei, Japan). During the test, the subject stands straight, with both feet on the ground; then, the subject reaches up as high as possible and returns to the same position as at the start. This was repeated twice, and the best score was recorded.
The modified 1 RM squat and deadlift were calculated as indicated by
Isokinetic muscular strength was measured as trunk extension and flexion (30°/sec) using the Biodex System 3 (BIODEX, USA). The test was repeated 3 times continuously. The final value was divided by body weight, and the best score was recorded.
The competition times were noted for both 50 m and 100 m swims from the 2013 conference pre-training times and 2014 conference post-training times.
The periodic training program consisted of combined linear and nonlinear training (
Resistance training was used to improve lower and core muscle strength (
The finswimming underwater exercise program was modified from that used by
Statistical analyses were performed using the Statistical Package for the Social Sciences (SPSS) version 18.0 for Window (IBM, Chicago, IL, USA). The results are expressed as means and standard deviations. The paired t-test was used to compare body composition, physical fitness, and competition times before and after training. Statistical significance was set as
As shown in
The finswimmers’ best scores during competitions in 2013 and 2014 were collected. As shown in
Our study demonstrates significant improvement in body composition and physical strength appropriate for swimming events as a result of 12 weeks of combined linear and nonlinear periodic training in high school finswimmers.
Swimmers generally have less than 10% body fat, although before training, our finswimmers had 20.04% body fat, and
In this study, flexibility, explosive muscular strength, and isotonic and isometric muscular strength of finswimmers, evaluated as factors related to athletic performance, all showed improvement after 12 weeks of combined training.
Flexibility means range of joint mobility, and it improves speed through increasing momentum and decreasing inner resistance of muscle (
Explosive muscular strength is the ability to move muscles quickly with explosive strength (
Maximum muscular strength, demonstrated by isotonic muscular strength, is an important factor in determining athletic performance (
Using isotonic training exercises as a measurement method enables precise muscular functional examination with various angular velocities as speed of motion changes according to the subject’s resistance (
In conclusion, linear and nonlinear combined training conducted over a 12-week short-term period is effective in improving athletic performance by improving body composition and physical strength appropriate for the sport of short-distance finswimmers. Additional training to improve flexural muscular strength needs to be added to the program for future research.
There are no potential conflicts of interest relevant to this article.
Subject characteristics
Group | Mean±SD |
---|---|
Age (yr) | 16.08± 1.44 |
Height (cm) | 172.68± 5.30 |
Weight (kg) | 72.99± 8.11 |
%fat (%) | 20.04± 3.70 |
FFM (kg) | 53.91± 4.45 |
Career (yr) | 3.78± 1.9 |
Linear periodic training program
Date | January | February | March | April | |
---|---|---|---|---|---|
Race period | Ready | Race 1 | Race 2 | ||
Exercise | Adaptation (2 weeks) | Maximal muscular strength (4 weeks) | Speed (2 weeks) | Power-endurance (2 weeks) | Maintains (2 weeks) |
Type | Circuit | Resistance | Resistance | Resistance | Resistance |
Intensity | 1 RM 40–70% | 1 RM 85–100% | 1 RM 75–85% | 1 RM 50–70% | 1 RM 80–85% |
Content | Little high | Moderate | Little high | Low | Little low |
4 sets | 5 sets | 4 sets | 5 sets | 3 sets | |
15–30 repetition | 4–8 repetition | 6–10 repetition | 15–30 repetition | 6–8 repetition | |
Speed | Aerobic endurance | Anaerobic power | Specific speed | Power-Endurance | Specific speed |
RM, Repetition maximum.
Resistance training program
Mon/Thur | Tue/Fri | |
---|---|---|
Warm-up | Running 10 min | Running 10 min |
Exercise type | Squat (Leg press) |
Dead lift, Bench press, Shoulder press, Bent over row, Lat pull down, Barbell curl, Leg raise |
Exercise method | 1–2 weeks | 4 sets, 15–30 reps, 40–70% RM intensity, 30–60 sec rest (exercise), 2–3 min rest (set) |
3–6 weeks | 5 sets, 4–8 reps, 85–100% RM intensity, 3–5 min rest (set) | |
7–8 weeks | 4 sets, 6–10 reps, 75%–85% RM intensity, 3–5 min rest (set) | |
9–10 weeks | 5 sets, 15–30 reps, 50%–70% RM intensity 5–7 min rest (set) | |
11–12 weeks | 3 sets, 6–8 reps, 80–85% RM intensity, 3 min rest(set) | |
Cool-down | Stretching 15 min | Stretching 15 min |
Reps; Repetition, RM; Repetition maximum.
Nonlinear underwater training program
Period | Time (week) | Mon | Tue | Wed | Thu | Fri | Sat | Intensity |
---|---|---|---|---|---|---|---|---|
Adaptation | 2 A.M | 4,300 | 4,700 | 4,500 | 4,300 | 4,200 | 4,300 | EN1, EN2 |
P.M | 2,250 | 3,000 | 2,200 | EN3, SP1 | ||||
Total (m/d) | 6,550 | 4,700 | 7,500 | 4,300 | 6,400 | 4,300 | ||
Maximal muscular strength | 4 A.M | 3,600 | 4,000 | 4,200 | 3,600 | 4,000 | 4,200 | EN2, EN3, SP1 |
P.M | 3,250 | 2,250 | 2,200 | EN3, SP1, SP2 | ||||
Total (m/d) | 6,850 | 4,000 | 6,650 | 3,600 | 6,200 | 4,200 | ||
Speed | 4 | 4,050 | 4,000 | 4,500 | 4,200 | 4,550 | 3,900 | EN2, EN3, SP1 |
Maintain | 2 | 3,650 | 3,525 | 3,250 | 3,800 | 3,400 | 3,200 | EN3, SP1, SP2 |
EN1, Basic endurance training; EN2, Threshold endurance training; EN3, Overload endurance training; SP1, Lactate tolerance training; SP2, Lactate production training.
Change of body composition
Variable | Pre | Post | t | |
---|---|---|---|---|
Weight (kg) | 72.52± 9.09 | 69.93± 8.34 | 4.689 | 0.001 |
BMI (kg/m2) | 24.28± 2.35 | 23.43± 2.28 | 4.877 | 0.000 |
%fat (%) | 19.60± 4.84 | 17.50± 4.75 | 4.249 | 0.001 |
Fat free mass (kg) | 53.75± 4.68 | 53.34± 4.58 | 1.735 | 0.111 |
BMI, Body mass index; Pre, Pre-training; Post, Post-training;
Change of physical fitness
Variable | Pre | Post | t | |
---|---|---|---|---|
Trunk flexion forward (cm) | 19.08± 5.31 | 20.56± 5.52 | −2.327 | 0.040 |
Trunk extension backward (cm) | 53.94± 5.76 | 57.01± 5.32 | −5.159 | 0.000 |
Sargent Jump (cm) | 51.16± 8.25 | 55.08± 9.40 | −2.707 | 0.020 |
Squat (kg) | 102.75± 27.75 | 124.67± 26.53 | −5.417 | 0.000 |
Dead lift (kg) | 68.00± 27.50 | 88.83± 29.56 | −6.108 | 0.000 |
Knee extension on right N (BW) | 280.55± 43.95 | 300.10± 27.17 | −2.353 | 0.038 |
Knee extension on left N (BW) | 281.70± 44.38 | 293.06± 31.24 | −1.533 | 0.153 |
Knee flexion on right N (BW) | 145.06± 21.06 | 153.27± 17.20 | −1.717 | 0.114 |
Knee flexion on left N (BW) | 141.17± 23.25 | 149.81± 18.14 | −2.175 | 0.052 |
Trunk extension N (BW) | 376.45± 50.39 | 449.16± 60.93 | −3.892 | 0.003 |
Trunk flexion N (BW) | 196.30± 42.71 | 233.72± 41.64 | −1.909 | 0.083 |
Competition time (sec) | 46.57± 4.77 | 43.88± 4.53 | 2.938 | 0.013 |
Pre, Pre-training; Post, Post-training;
Competition times
Race | A | B | Difference (B-A) | |
---|---|---|---|---|
1 | Apnea 50 m | 15:70 | 15:40 | 00:30 |
Surface 100 m | 38:56 | 37:52 | 01:04 | |
2 | Surface 50 m | 19:70 | 18:71 | 00:99 |
Surface 100 m | 43:76 | 42:66 | 01:10 | |
3 | Surface 50 m | 19:90 | 19:90 | 00:00 |
Surface 100 m | 45:10 | 44.65 | 00:45 | |
4 | Surface 50 m | 20:60 | 20:40 | 00:20 |
Surface 100 m | 45:30 | 43:63 | 01:67 | |
5 | Apnea 50 m | 20:00 | 17:80 | 02:20 |
surface 100 m | 45:60 | 40:90 | 04.70 | |
6 | Surface 50 m | 23:40 | 22:69 | 00:71 |
Surface 100 m | 53:30 | 49:92 | 03:38 | |
7 | Apnea 50 m | 18:01 | 17:24 | 00:77 |
Surface 100 m | 46:80 | 46:30 | 00:50 | |
8 | Apnea 50 m | 17:10 | 16:87 | 00:23 |
Surface 100 m | 38:90 | 36.99 | 00:45 | |
9 | Surface 50 m | 22:83 | 22:07 | 00:76 |
Surface 100 m | 52:00 | 50:18 | 01:82 | |
10 | Surface 50 m | 21:41 | 20:42 | 00:99 |
Surface 100 m | 51:88 | 46:48 | 05:40 | |
11 | Surface 50 m | 21:70 | 21:15 | 00:55 |
Surface 100 m | 47:80 | 47:61 | 00:19 | |
12 | Surface 50 m | 22:30 | 21:80 | 00:50 |
Surface 100 m | 51:20 | 50:00 | 01:20 |
A: 2013’ race record, B: 2014’ race record.