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tion have often been linked to bone improvements. However, not all sports have the same effects, being non-osteogenic sports such as swimming defined as negative or neutral sports to practice regarding bone mass by some authors, similarly exercise- diet interaction in especific groups is still not clear. Objective:To present the methodology of the RENACI- MENTO project that aims to evaluate body composition and more specifically bone mass by several techniques in adolescent swimmers and to observe the effects and perdurability of whole body vibration (WBV) and jumping intervention (JIN) on body composition and fitness on this population and explore posible diet interac- tions. Design:Randomized controlled trial. Methods:78 swimmers (12-17 y) and 26 sex- and age- matched controls will participate in this study. Dual energy X-ray, peripheral Quantitative Computed Tomography, Quantitative Ultrasound, Bioelectrical Impedance Analysis, and anthropometry measurements will be performed in order to evaluate body composition. Physical activity, nutrition, pubertal development and socio-economical status may act as confounders of body composition and therefore will also be registered. Several fitness factors regarding strength, endurance, perfor- mance and others will also be registered to evaluate differences with controls and act as confounders. A 7- month WBV therapy will be performed by 26 swimmers consisting of a training of 15 minutes 3 times per week. An 8 month JIM will also be performed by

and therefore will also be registered. Several fitness factors regarding strength, endurance, perfor- mance and others will also be registered to evaluate differences with controls and act as confounders. A 7- month WBV therapy will be performed by 26 swimmers consisting of a training of 15 minutes 3 times per week. An 8 month JIM will also be performed by 26 swimmers 3 times per week. The remaining 26 swimmers will continue their normal swimming training. Four evalua- tions will be performed, the first one in order to describe differences between swimmers and controls. The second Correspondence: Germán Vicente Rodríguez. GENUD (Growth, Exercise, NUtrition and Development) Research Group. Faculty of Health and Sport Sciences. University of Zaragoza. Edificio SAI 2ª planta. Zaragoza. Spain. E-mail: gervicen@unizar.es Recibido: 15-V-2014. Aceptado: 10-VI-2014. 24. SWIMMING_01. Interacción 05/09/14 09:00 Página 399

Abbreviations BIA: Bioelectrical impedance analysis. BMD: Bone mineral density. BMC: Bone mineral content. BUA: Broadband ultrasound attenuation. CFQ: Calcium frequency questionnaire. DXA: Dual energy X-ray. JIN: Jumping intervention. MICS: Maximum isometric cuadriceps squat. pQCT: Peripheral quantitative computed tomo- graphy. QUS: Quantitative ultrasound. RCT: Randomized Controlled Trial. SOS: Speed of sound. SES: Socio-economical status. WBV: Whole body vibration training. Introduction It is well known that physical activity has a positive effect on bone mass, and that practiced during growth periods may improve bone acquisition. 1 However, not all sports have the same effects on bone mass. Recent literature suggests that high impact sports such as volleyball or basketball submit bones to higher strains producing increments in bone mineral density (BMD) and bone mineral content (BMC) 2 and may improve bone structure. 3 Other sports like cycling 4 or swimming that are known as non-impact sports have shown to be less beneficial for bone health than high impact sports being described by some authors as negative sports to practice regarding bone mass. 5 Focusing on swimming, a recent systematic review 6 with 52 studies included, concluded that swimmers presented similar BMD and BMC values than seden- tary controls, but these results were not conclusive due to the heterogeneity of the included studies. Neverthe- less, swimmers presented lower values when they were compared to high-impact sports in all of the studies included in the review. However, the few studies that evaluated bone with peripheral quantitave computed tomography (pQCT) showed that swimmers presented a better structure than sedentary controls. Higher values of bone turnover were also found, suggesting therefore that although swimmers may present similar BMD and BMC values than controls both measured with Dual energy X-ray (DXA), swimmers might present a higher bone quality than sedentary controls. Most of the studies included in the previous review had reduced sample sizes (n = 20 in most of the studies) to compare with other sports, moreover the authors of the review state that several studies usign DXA did not adjust by any covariables and therefore results migth have been masking the real effects of swimming.

quality than sedentary controls. Most of the studies included in the previous review had reduced sample sizes (n = 20 in most of the studies) to compare with other sports, moreover the authors of the review state that several studies usign DXA did not adjust by any covariables and therefore results migth have been masking the real effects of swimming. Out of the 52 studies included in the review only 22 included adolescent swimmers and out of these, only 2 included more than 50 swimmers. Moreover, none of the studies including adolescents used pQCT to eval- uate bone structure. Therefore, we propose the following questions: 1. Is swimming negative for bone mass acquisiton during adolescence, or does it not have any effect at all in this population? 2. If it is negative, is there a threshold regarding hours of swimming when this activity becomes negative? And regarding years of swimming? 3. If bone structure is analyzed by two methods (pQCT and ultrasound), will there be differences between methods and are swimmers bones stronger, similar or weaker than sedentary controls? 4. Is bone improved with 3 sessions of 15 minutes of whole body vibration training (WBV) or jumping intervention (JIN) complementary to swimming training? 5. If bone is improved with 45 minutes of WBV or JIN per week, what it the perdurability of these effects? 6. Is bone turnover affected by swimming? 7. How does diet interact with exercise and its combined effect on bone mass, estructure and metabolism? 400 A. Gómez-Bruton et al.Nutr Hosp. 2014;30(2):399-409 one to describe the effects of the interventions and the third and fourth evaluations to describe the perdurability of the effects of the WBV and JIN. Conclusion:The RENACIMIENTO project will allow to answer several questions regarding body composition, fitness, bone mass and interaction with diet of adolescent swimmers, describe swimming as a positive, negative or neutral sport to practice regarding these parameters and elucidate the effects and perdurability of WBV and JIM on body composition. (Nutr Hosp. 2014;30:399-409) DOI:10.3305/nh.2014.30.2.7603 Key words: Swimmers. Osteoporosis. Bone mass. pQCT. DXA. y la tercera y cuarta para evaluar la

regarding body composition, fitness, bone mass and interaction with diet of adolescent swimmers, describe swimming as a positive, negative or neutral sport to practice regarding these parameters and elucidate the effects and perdurability of WBV and JIM on body composition. (Nutr Hosp. 2014;30:399-409) DOI:10.3305/nh.2014.30.2.7603 Key words: Swimmers. Osteoporosis. Bone mass. pQCT. DXA. y la tercera y cuarta para evaluar la perdurabilidad de estas intervenciones. Conclusión:El proyecto RENACIMIENTO permitirá contestar a diversas preguntas relacionadas con la com- posición corporal, condición física y masa ósea de los nadadores adolescentes y el posible efecto combinado dieta-ejercicio en esta población. Definirá la natación como un deporte positivo, neutral o negativo en relación con estos parámetros y esclarecerá los efectos y perdura- bilidad de la WBV y JIN sobre la composición corporal. (Nutr Hosp. 2014;30:399-409) DOI:10.3305/nh.2014.30.2.7603 Palabras clave:Nadadores. Osteoporosis. Masa ósea. pQCT. DXA. 24. SWIMMING_01. Interacción 05/09/14 09:00 Página 400

These and other questions should be answered, specially in this age-population where bone is constantly developing. The idea that “senile osteoporosis is a paedi- atric disease” is increasingly accepted. 3 In fact, the World Health Organization proposed prevention as the most powerful way to fight against the non-communicable diseases, i.e. osteoporosis. 7 Adolescence is therefore a critical period for bone development and the effect of intense swimming training on bone should be carefully studied in order to evaluate and avoid bone diseases in this population later in life. All of the previous questions and the need of describing the art-of-the-state in adolescent swimmers have been the beginning of the RENACIMIENTO project that aims to answer most of these interrogants and elucidate the real effect of swimming on bone mass measured by several different techniques. With this report we aim to present the general methodology of this wide research project as a way to offer a commun comprehensive methodology in this research field. Material and methods Arguments for publishing a desing paper The present paper is going to describe a randomized controlled trial (RCT) assessing a WBV and JIN in adolescent swimmers which will take place over a swim- ming season. Publishing the design and rationale of a RCT before the results are available has important bene- fits. The study can be critically evaluated for its method- ological quality, irrespective of the results. Moreover, if a design paper is written and published, the results will most probably be published, even if they are negative. In addition, a design paper includes a more detailed descrip- tion of the study techniques, the intervention and all outcome measures than what can be reported in the method section of a regular publication focusing only on part of the study results. This methological paper can help researchers from similar fields to compare methods and obtain a global view of the project. Ethical committee The protocol study has been aproved by the Ethics Committee of Clinical Research from the Government of Aragón (C.I.PI11/0034; CEICA; SPAIN), and will follow the ethical guidelines of the Declaration of Helsinki 1961

part of the study results. This methological paper can help researchers from similar fields to compare methods and obtain a global view of the project. Ethical committee The protocol study has been aproved by the Ethics Committee of Clinical Research from the Government of Aragón (C.I.PI11/0034; CEICA; SPAIN), and will follow the ethical guidelines of the Declaration of Helsinki 1961 (revision of Edinburgh 2000), demanding in all cases the signed informed consent by the adoles- cent participant and his parents or tutors. Study sample The RENACIMIENTO study will evaluate 78 adoles- cent swimmers of both sexes aged from 12 to 17 years old and 26 adolescent sedentary sex- and age-matched controls not involved in any specific sport participation. All the participants will be healthy adolescents that will not take any drugs affecting bone mass. The sample size has been calculated in regard to the variable with most variability BMD. An independet t- test was performed in order to attain a power of 99% to detect differences in the contrast of the null hypothesis H 0 : 1 = 2. Statistical level of significance was set at 1%, and assuming that the mean from the reference group was 1.25 units, the mean of the experimental group 1.20 units and the standard deviation of both groups was 0.02 units it would be necessary to include 10 experimental units in the reference group and 10 in the experimental groups, making a total of 40 experimental units in the study. However, the number of participants to include in a study, also depends of the possible loss of participants: n’ = n/(1-p), so if loss were of 30% (possible lost), the number of subjects to recruit would be n’ = 10/(1-0.3) = 12.5 subjects = 13 subjects in each group. As there are 4 groups (swimmers; swim- mers+WBV, swimmers+JIN intervention, controls) and each group is duplicated by sex it makes a total of 104 adolescents (4 groups x 13 participants per group x 2 genders = 104 participants). Study design The RENACIMIENTO project is a RCT with follow-up period (fig. 1) where swimmers and controls

13 subjects in each group. As there are 4 groups (swimmers; swim- mers+WBV, swimmers+JIN intervention, controls) and each group is duplicated by sex it makes a total of 104 adolescents (4 groups x 13 participants per group x 2 genders = 104 participants). Study design The RENACIMIENTO project is a RCT with follow-up period (fig. 1) where swimmers and controls will be measured in 4 ocassions. The first measurement was performed in September- October 2012. The intervention has been performed, although no results from the first cohort nor the inter- vention have been published yet. The second measurement took place in May-June (swimmers) 2013. The effect of WBV, JIN and swim- ming on bone and body composition during a whole season in adolescent swimmers will be described with this measurement. The third measurement will take place in February- March, 2014. This measurement will evaluate the perdurability of the effect of the WBV and JIN (if there were any) 9 months after the intervention. The last measurement will take place in September- October, 2014. With this last measurement we intend to elucidate the perdurability of the effects produced by WBV and JIN on body composition after 18 months. Equipment All the used equipment is summarized in table I. Body composition is the main outcome that we intend to measure. However, other factors such as physical activity, nutrition, pubertal development or socio- economical status may act as confounders and there- fore must also be recorded. Swimming training repercussion on metabolic and structural bone development 401Nutr Hosp. 2014;30(2):399-409 24. SWIMMING_01. Interacción 05/09/14 09:00 Página 401

Evaluation B ODY COMPOSITION One of the main aims of the RENACIMIENTO study is to evaluate bone mass which is the single most important determinant of future fracture. 8 Several tech- niques have been designed for this purpose. Included bone mass measurements in this project have been DXA, pQCT and quantitative ultrasound. D UAL ENERGYX-RAY DXA is the most common photon absorptiometry method used to evaluate bone mass, and has been defined by the WHO as the gold standard method for evaluating osteoporosis. It is a two dimensional measure highly influenced by body size. 9 It therefore seems necessary to adjust by covariates to minimize the differences among participants when these are compared. The used equipment for the current project will be an Hologic QDR 4500 scanner (paediatric version of the software QDR-Explorer, Hologic corp., Software version 12.4, Bedford, MA, USA). This device uses two X-ray beams to distinguish between fat and lean tissues on the one hand and bone and soft tissues on the other, on the basis of the extent to which the pairs of tissues attenuate the two X-rays to different degrees. DXA equipment will be calibrated daily using a lumbar spine phantom as recommended by the manu- facturer. All DXA scans will be completed with the same device and software and performed by the same technician who has been fully trained in the operation of the scanner, the positioning of subjects, and the analysis of results, according to the manufacturer’s guidelines. Fat mass, fat-free mass and bone mass are calculated using a computer algorithm provided by the manufacturer. A whole body scan will be performed 402 A. Gómez-Bruton et al.Nutr Hosp. 2014;30(2):399-409 Fig. 1.—Chronological design of the RENACIMIENTO project. SW + WBV 26 SW + PLI 26 SW26 SW CG SW CG SW CG SW CG SE OC NO DE JA FE MA AP MY JN JL AU SE OC NO DE JA FE MA AP MY JN JL AU SE 1 2 3 4 5 6 7 8 9 1011 1213141516171819202122232425 9 Months 18 Months (9 months perdurability WBV) 24 Months (15 months perdurability WBV)

26 SW26 SW CG SW CG SW CG SW CG SE OC NO DE JA FE MA AP MY JN JL AU SE OC NO DE JA FE MA AP MY JN JL AU SE 1 2 3 4 5 6 7 8 9 1011 1213141516171819202122232425 9 Months 18 Months (9 months perdurability WBV) 24 Months (15 months perdurability WBV) SW = Swimmers; CG = Control group; WBV = Whole body vibration; PLI = Pilometric training. Chronogram begins in September 2012 and ends on September 2014 Table I pQCT intra-measures coefficient of variation Measure Zone % coeficient of evaluation of variation Radius Total area 4% 4.26 Total density 4% 2.25 Trabecular area 4% 4.27 Trabecular density 4% 2.78 Total area 66% 2.42 Total density 66% 2.07 Cortical area 66% 2.44 Cortical density 66% 0.84 Cortical thickness 66% 3.60 Periosteal circumference 66% 1.21 Endosteal circumference 66% 2.98 Muscle area 66% 1.34 Fat area 66% 7.81 Tibia Total area 4% 0.82 Total density 4% 0.67 Trabecular area 4% 0.83 Trabecular density 4% 0.90 Total area 38% 4.36 Total density 38% 1.27 Cortical area 38% 5.31 Cortical density 38% 0.49 Cortical thickness 38% 4.61 Periosteal circumference 38% 2.33 Endosteal circumference 38% 2.38 Muscle area 66% 1.69 Fat area 66% 3.88 24. SWIMMING_01. Interacción 05/09/14 09:00 Página 402

allowing a regional analysis (upper and lower extremi- ties and pelvic region). The arm region from the regional analysis includes the hand, forearm and arm and is separated from the trunk by an inclined line crossing the scapulohumeral joint such that the humeral head is located in the arm region. The leg region includes the foot, lower leg and upper leg and is defined by an inclined line passing just below the pelvis crossing the neck of the femur. The head region comprises all skeletal parts of the skull and cervical vertebra above a horizontal line passing just below the jabone. In addition to this whole body scan a lumbar spine, hip and forearm scans will be performed. To save time and reduce x-ray exposure, only the non- dominant hip and forearm will be scanned. Values for the femoral neck, Ward’s triangle, greater trochanter, and intertrochanteric subregions are provided from the hip scan. The Ward’s triangle is defined as the area (approximately 1.1 cm 2 ) of the femoral neck with the lowest BMD. Values reported for the lumbar vertebrae L2-L4 are obtained from an anteroposterior lumbar scan and expressed as the mean BMD of the three vertebrae. Values reported for the forearm are ultra- distal, mid and 1/3 radius and ulna. The coefficients of variation of the DXA in our lab are published else- where. 10 PERIPHERALQUANTITATIVECOMPUTEDTOMOGRAPHY In contrast to DXA, pQCT measures volumetric BMD and allows for separate assessment of trabecular and cortical bone of the appendicular skeleton, such as the radius and tibia. 8 This device provides measures of cross-sectional areas related to bone size (area), mass (mineral content), apparent tissue density and geom- etry (spatial distribution of mass). Moreover, this device calculates strength indices, which combine bone cross-sectional geometry and tissue density measures. Our equipment is a XCT 2000 Peripheral QCT Scanner, Ortometrix, INC that allows measure- ment of the tibia and radius. For the present study we will use both non-dominant limbs. Coefficients of vari- ation for pQCT in our laboratory have been calculated for several variables and are summarized in table 1. For the