The elite child athlete is one who has superior athletic talent. Monofin (a single surface swim fin) swimming has already proved to be the most efficient method of swimming for human beings [11]. It is a sport of speed practiced on the surface or under water [9].

The purpose of this study was to examine the influence of long-term monofin training (LTMT) [36 weeks of surface training, 6 sessions per week, 90 minutes per session] on cardiopulmonary adaptation in elite child athletes.

14 elite monofin using children (3 girls and 11 boys) aged 11.95 years (± 1.09yr), height (Ht) (153.07± 4.2 cm), weight (Wt) (52.4 ± 3.7 kg ), body surface area (BSA.m2 1.48 ± 5.6 m2 ), took part in LTMT for 36 weeks. All subjects underwent pulmonary function and max. Vo2 tests before and after the LTMT. Static and dynamic lung volume parameters (FVC, ERV, IRV, TV, IC, FEV1, MVV.TLC) were measured using a Spirometric test and bicycle ergometer exercise test with expiratory gas analysis (Vo2 max ). Statistical methods of SPSS, means ± SD and paired t test were used.

There was significant difference for all cardiopulmonary parameters and max. Vo2 after LTMT, as shown in table 2. The present findings imply that the quantity and duration of monofin training undertaken increased lung volumes and max. Vo2. These positive physiological adaptations suggest that long term monofin training can be considered a useful activity for improving fitness in prepubescent children.

While it is important for children and young adults to engage in athletic activities, it is equally important to closely monitor their development toward conditioning training. Sport provides a positive environment that may enhance the physical growth and physiological development of children. The study of training effects on a child’s cardiopulmonary function has become of great interest to scientists of exercise physiology, with elite child athletes becoming one of the scientific topics that encourages discussion and leads to more studies and research. Many studies agree that regular training programs make morphological changes to the lung and reparatory muscle and those changes vary according to the kind of sports activity (Abouzeid Magdy, 2007). Regular exercise is necessary to develop and maintain an optimal level of health and performance. Development in athletic performance has aroused considerable interest in what morphological qualities characterise successful athletes. The elite child athletes is one who has superior athletic talent and requires appropriate training and coaching to ensure a safe and healthy athletic career and promote future wellbeing . Despite the increasing involvement of child athletes in intensive training regimens, little is know about the influence of monofin training on cardiopulmonary capacity in pre-pubertal children. The respiratory system is challenged during surface and under water exercise due to increased hydrostatic pressure and breathing resistance. To be competitive at a high level requires training regimens for children that could be considered extreme even for adults. The long-term health consequences of intense training in young athletes needs to be further investigated. There appear to be increasing numbers of children who specialise in a sport at an early age, train year–round for a sport and/or compete on an "elite" level. The successes of young athletes can serve as powerful inducement for others to follow. Until recently, pulmonary limitations to oxygen transport in child athletes during sub-maximal exercise were not considered to limit exercise performance (Shell, 2002).

Monofin swimming is swimming with an aid of a single-bladed swim fin, firstintroduced in 1972 at the Fin Swimming Championships in Moscow. The primary movement in monofin swimming is the forward undulation of the hip and descendant impulse of the legs. The main source of power derives from the swimmer's midsection, involving the lower abdominal and back muscles, buttocks and quadriceps. Monofin swimmers extend arms forward and lock their hands together, blocking the head between the biceps. The undulating movement starts in the shoulders, with maximum amplitude towards the hips; the legs almost do not bend to transfer the momentum of the movement. This technique is called a dolphin kick.

Movement through water requires propulsion and energy to drive the system Use of fins is very important to overcome water resistance and increase propulsion. While swimming with fins is only 20% as efficient as walking or running on dry land, the energy cost when swimming with fins is about 40% lower than when swimming without them (Zamparo et al, 2007) . Fins provide thrust to overcome drag and propel the swimmer underwater (Pendergust, et al, 2003). Concerning fin swimming at the surface, Zamparo et al (2002) performed a kinematics study that quantified the efficiency of human swimming in using fins. Describing the physics and physiology of fin swimming during monofin training, the inspiratory muscles must overcome a resistive load to maintain ventilation. Kubiak (2005) showed that inspiratory airflows were significantly higher in swimmers who trained regularly for 7-8 years. The finding appears to be due to the effect of training on inspiratory muscles.

Our study was carried out due lack of knowledge regarding monofin training effects and cardiopulmonary adaptation in children.

Subjects 14 elite monofin children (3 girls and 11 boys; aged (11.95±10.9 years), HT (153.07±4.2 cm ) , WT (52.4±3.7kg), body surface area (BSAm2 1.48±5.6m2), took part in (LTMT) for 36 weeks monofin training, all subjects under went anthropometry and pulmonary function test and max Vo2 test before and after LTMT.

Anthropometric tests. Body weight was recorded to the nearest 0.1 kg with a digital weight scale (Seca 841, Seca Gmb H, Hamburg, Germany) and body height (Holton, Crymyeh, Uk) to the nearest millimetre. Body surface area (BSAm2) was determined from height (HT) and weight (WT) according Du Bois formula (7).

Each subject was given a spirometry test using a chest test spirometer (Vacuumed Vendetta CA) before the Vo2 max test both pre- and post- training. Each subject stood facing the spirometer and performed a maximal inhalation followed by a forceful exhalation into the tube until all air was expelled. The chest test spirometer provided forced vital capacity (FVC), forced expiratory volume in one second (FEV1), FVE/FVC ratio, peak inspiritory and expiratory flow rate (PEF). Lung function tests provide qualitative and quantitative evaluation of pulmonary function. Lung volumes reflect the individual's ability to increase the depth of breathing and capacities are simply a combination of two or more lung volumes (Abouzeid 1983).

Testing was conducted in an air-conditioned laboratory with a temperature of 20 to 21oC. Subjects were encourage to exercise to exhaustion while cycling in the upright position on a mechanically braked ergo meter (model 868,monark, Stockholm, Sweden). Cycling cadence was maintained at 50 revolutions per minute. Prior to testing, seat height was adjusted to suit each subject.

Altogether, 14 elite child monofin athletes, (3 girls and 11 boys) took part in a long-term monofin training program consisting of 36 weeks of training times per week, 90 min per unit in a local pool (50 m length) of approximately 216 sessions. The intensity of the training was always adjusted according to pulse rate. The training units contained aerobic and anaerobic training; the aerobic component was achieved by training over long distances, interval method and fartlek methods were then used for anaerobic training (containing speed, repetition and the hypoxic method (controlled breathing), with incremental work load of 75% to 90% of max. heart rate. Average daily distance was 3000– 4800 metres/session with energy systems used at 80% aerobic and 20% anaerobic. The basic session goals were: emphasis on building aerobic conditioning by training all four strokes and increasing distance; learning refined race tactics; introduction to dry land; introduction to tempo and rhythm in all strokes; continuing to develop stronger kick strength and speed. Emphasis to the five steps to monofin technique were: streamline (extend arms as far as possible and overlap hands); hunch the neck and the shoulders slightly (while streamlined, slightly hunch without dropping the hands or head drive the leg with heels up and knees slightly bent); hips forced up (as the feet drive down, the body's undulation reaches accentuate the power of the downward kick); hips slide forward up (thrust the hips forward and more quickly for the propulsive downbeat). In addition, there were educational goals for the program around the athletes learning about nutrition and energy sources, concepts of growth and how to compete after having to travel to an event.

The Dry Land Program included stretching 2-3 times/week and other activities such as a body weight circuit (push ups/sit up etc.), running games and introduction to medicine balls.

Mean (±SD) pre- and post- long-term monofin training on cardiopulmonary function values appears in Figure 2. There were a significant changes were noted. There were percentage improvements in IRV (54.5 %), PEF (48.1%), TLC (47.81%), IC (47.15%), FEV1 (47.03%), RR (46.8%), FVC (45.12%), max. Vo2 (43.1%), ERV (41.18%), VT (26.6%), MVV (25.2%), FEV1 /FVC (16.12%), resting HR (14.79%), max HR (9.12%).

To our knowledge, this is the first study undertaken in a population of prepubertal children to investigate cardiopulmonary adaptation using monofin training in elite children athletes. The understanding of a child's capacity for intensive training is limited. Lung function tests provide qualitative and quantitative evaluation of pulmonary function, which is the key component of oxygen uptake. Pulmonary function increases similarly in boys and girls with growth and training, before puberty, and regular physical training in young athletes causes adaptive structural and function changes in the cardiorespitory system (4, 6, 10, 15, 17). Results from the study showed significant difference (p <0.01) in the lung function and max Vo2 as shown in table 2.

The mechanics of moving a body through water is achieved through the musculoskeletal system, with the skeleton providing the structural support and arms the lever for muscle movement. Monofin training enhances ventilatory muscular endurance and improves lung capacity and breath control. The phenomenon of increased dynamic and static lung volumes in this study can be attributed to a number of factors: increased inspiratory and expiratory resistance, leading to an increase in the work of breathing. The physical stress imposed by the LTMT exercises, together with increased work of breathing, produces a breathing pattern characterised by high tidal volume, which is maintained for prolonged periods. A pervious study (5) demonstrated that inspiratory muscular strength training and conditioning of the accessory muscle of the neck and chest wall may be important in expanding the chest to large lung volumes, and can cause a shift in the optimal length of the inspiratory muscles such that larger forces can be generated at a shorter muscle length.

The increase observed in our results, in both dynamic and static lung volumes, is a result of cardiopulmonary adaptation due to the effects of monofin training on the respiratory muscles. It is possible that larger lungs (an increased FVC, TLC etc) may be due to hypertrophy of the thoracic wall and diaphragm muscles. This might be a training effect of breathing against an increased respiratory load. In turn, the stronger respiratory muscle might be facilitated by the increased workload of breathing during monofin training. Wyle Gala et al (2007) reported that targeted respiratory muscle training improves respiratory muscle strength and underwater swimming performance.

Little has been done to explore the impact of elite-level training on children participating in monofin swimming training. The purpose of this study was to examine the influence of long-term monofin swimming training of 36 week, six times per week on cardiopulmonary adaptation in elite child athletes. The results indicate that long–term monofin training during pre-puberty enhances static and dynamic lung volume. As to the causative mechanism, it can be speculated that at pre-puberty, long-term monofin training promotes lung growth by harmonising the development of the respiratory system and improves physical working capacity by exercise Vo2 max test and decreases resting and max. heart rate/beats/min. The more rapid cardiopulmonary responses noted in child athletes seemed directly related to the degree of specific training. More research is needed to fully understand the endurance trainability of young athletes. More work is still needed with regard to younger age groups, particularly during the prepubescent and pubescent years. These results raise questions about the effect of types of monofin swimming on myocardial adaptation and further research is needed to define with more precision the different cardiovascular functions of young athletes.