The effect of shuttle test protocol and the resulting lactacidaemia on maximal velocity and maximal oxygen uptake during the shuttle exercise test

Effects of Sand Surface Plyometric and Sprint Training on Physical and Technical Skill Performance in Beach Handball Players

This study compared the effects of a 6-week combined plyometric and sprint-training program on the sand to regular preseason training, on the athletic performance and technical actions of beach handball (BH) players. Athletes were randomly assigned either to the control (CG, n = 12; BH training only) or the experimental group (EG, n = 12; plyometric + sprint + BH training). Assessments conducted before and after the training period included a squat jump, a countermovement jump, the Abalakov jump, a 15-m sprint, a modified Course-Navette endurance test, and four sport-specific BH throwing speed tests: a standing penalty throw, a 3-step running throw, a jump throw, and a 360º jump throw. The training intervention enhanced all athletic performance measures (all, p < 0.05). In contrast, the only improvement in the CG included endurance performance (p< 0.05). Significant time-group differences were noted in favor of the EG compared to the CG (p< 0.05) in the squat jump, the countermovement jump, the Abalakov jump, the jump throw velocity and 360º jump throw velocity. In conclusion, compared to BH regular training, 6 weeks of sand surface preseason plyometric and sprint training combined with regular BH training induced greater improvements in athletic performance and specific skills in BH players.

Applicability of Field Aerobic Fitness Tests in Soccer: Which One to Choose?

A desire to make fitness testing cheaper and easier to conduct in a team-sport setting has led to the development of numerous field aerobic fitness tests. This has contributed to a growing confusion among strength and conditioning coaches about which one to use. The main aim of this narrative review was to examine the reliability, validity, sensitivity and usefulness of the commonly used field aerobic fitness tests and to provide practical guidelines for their use in soccer. The University of Montreal track test (UMTT) and Vam Eval test seem the best options for estimation of maximal oxygen uptake (VO_2max) while the highest signal-to-noise ratio of the 30-15 intermittent fitness test (30-15IFT) suggests its superior sensitivity to track changes in fitness. The UMTT and 30-15IFT are the best solutions for prescription of long and short high-intensity interval training sessions, respectively. All field tests mostly present with marginal usefulness, but the smallest worthwhile change for UMTT or Vam Eval test, Yo-YoIRT2 and 30-15IFT are smaller than their stage increment making the improvement of only one stage in the test performance already worthwhile. Strength and conditioning coaches are advised to choose the test based on their specific purpose of testing.

Respiratory responses and rating of perceived exertion of severely obese adolescents during continuous and intermittent graded walking protocols: Application to cardiorespiratory field tests

During 20 m shuttle tests, obese adolescents may have difficulty achieving maximum cardiorespiratory performance due to the presence of braking-relaunch phases (BRP). Nineteen obese adolescents aged 15.2 ± 1.5 years (body mass index [BMI] = 39.7 ± 5.9 kg.m^-2) performed three graded walking exercises on a 50 m track at speeds between 3 and 6 km/h: a continuous-straight-line protocol (C), a continuous protocol that required turning back every 30 sec (C-BRP) and an intermittent protocol that consisted of successively walking then resting for 15 sec (15-15). Oxygen uptake (VO₂), aerobic cost of walking (Cw), ventilation (VE) and rating of perceived exertion (RPE) were measured at each stage during the protocols. During C-BRP, the responses were not significantly higher compared with C (p > 0.30). During 15-15, the VO₂, Cw and VE were ~ 15 to 25% lower than during C beginning at 4 km/h (p < 0.05). In obese adolescents, the respiratory impact of sudden directional changes during the 20 m shuttle-type test appeared to be minor at walking speeds. During the 15-15 test, the intensity increases more progressively, and this design may encourage obese adolescents to walk further than during a continuous test.

Effects of 6 Weeks of Different High-Intensity Interval and Moderate Continuous Training on Aerobic and Anaerobic Performance

Cavar, M, Marsic, T, Corluka, M, Culjak, Z, Cerkez Zovko, I, Müller, A, Tschakert, G, and Hofmann, P. Effects of 6 weeks of different high-intensity interval and moderate continuous training on aerobic and anaerobic performance. J Strength Cond Res 33(1): 44-56, 2019-To provide practical data, we compared the training effects of 3 different programs, using a shuttle run stimulus, on aerobic and anaerobic performance, measured using the 20-m maximal shuttle run (Beep) test and 300-yd shuttle run, respectively. Forty-five physically trained men, with a mean age of 21.1 ± 1.8 years, participated. The 6-week, 12-session training programs included 2 high-intensity interval training (HIIT) protocols, with either a short (SH) or long (LH) shuttle run interval, and a continuous shuttle run (CON), which was used as a control. The training intensity was based on the maximal shuttle run speed (MASS), measured on the Beep test, to elicit the relevant values of the time to exhaustion (TTE). Short (SH) training was performed at 115-120%(MASS), with a 10-second work to 10-second rest scheme, and the number of repetitions to be completed set to 70% of each participant's maximum (∼15 repetitions). LH training was performed at an intensity of 90-95%(MASS), with the duration set to 70%(TTE) (∼4 minutes). For both SH and LH, 3 sets were completed at each session, with a 2-3 minutes of rest between sets. CON training consisted of continuous shuttle running for 35 minutes at an intensity of 70%(MASS). Both SH and LH yielded a large training effect (p < 0.01), with SH preferentially improving anaerobic performance and LH preferentially improving aerobic performance. No effect of CON training was identified. Our findings indicate that these different training protocols cannot be used interchangeably and that the Beep test is useful in prescribing the intensity and duration of HIIT.

High-intensity intermittent training in hypoxia: a double-blinded, placebo-controlled field study in youth football players

This study examined the effects of 5 weeks (∼60 minutes per training, 2 d·wk) of run-based high-intensity repeated-sprint ability (RSA) and explosive strength/agility/sprint training in either normobaric hypoxia repeated sprints in hypoxia (RSH; inspired oxygen fraction [FIO2] = 14.3%) or repeated sprints in normoxia (RSN; FIO2 = 21.0%) on physical performance in 16 highly trained, under-18 male footballers. For both RSH (n = 8) and RSN (n = 8) groups, lower-limb explosive power, sprinting (10-40 m) times, maximal aerobic speed, repeated-sprint (10 × 30 m, 30-s rest) and repeated-agility (RA) (6 × 20 m, 30-s rest) abilities were evaluated in normoxia before and after supervised training. Lower-limb explosive power (+6.5 ± 1.9% vs. +5.0 ± 7.6% for RSH and RSN, respectively; both p < 0.001) and performance during maximal sprinting increased (from -6.6 ± 2.2% vs. -4.3 ± 2.6% at 10 m to -1.7 ± 1.7% vs. -1.3 ± 2.3% at 40 m for RSH and RSN, respectively; p values ranging from <0.05 to <0.01) to a similar extent in RSH and RSN. Both groups improved best (-3.0 ± 1.7% vs. -2.3 ± 1.8%; both p ≤ 0.05) and mean (-3.2 ± 1.7%, p < 0.01 vs. -1.9 ± 2.6%, p ≤ 0.05 for RSH and RSN, respectively) repeated-sprint times, whereas sprint decrement did not change. Significant interactions effects (p ≤ 0.05) between condition and time were found for RA ability-related parameters with very likely greater gains (p ≤ 0.05) for RSH than RSN (initial sprint: 4.4 ± 1.9% vs. 2.0 ± 1.7% and cumulated times: 4.3 ± 0.6% vs. 2.4 ± 1.7%). Maximal aerobic speed remained unchanged throughout the protocol. In youth highly trained football players, the addition of 10 repeated-sprint training sessions performed in hypoxia vs. normoxia to their regular football practice over a 5-week in-season period was more efficient at enhancing RA ability (including direction changes), whereas it had no additional effect on improvements in lower-limb explosive power, maximal sprinting, and RSA performance.

High-intensity interval training, solutions to the programming puzzle. Part II: anaerobic energy, neuromuscular load and practical applications

High-intensity interval training (HIT) is a well-known, time-efficient training method for improving cardiorespiratory and metabolic function and, in turn, physical performance in athletes. HIT involves repeated short (<45 s) to long (2-4 min) bouts of rather high-intensity exercise interspersed with recovery periods (refer to the previously published first part of this review). While athletes have used 'classical' HIT formats for nearly a century (e.g. repetitions of 30 s of exercise interspersed with 30 s of rest, or 2-4-min interval repetitions ran at high but still submaximal intensities), there is today a surge of research interest focused on examining the effects of short sprints and all-out efforts, both in the field and in the laboratory. Prescription of HIT consists of the manipulation of at least nine variables (e.g. work interval intensity and duration, relief interval intensity and duration, exercise modality, number of repetitions, number of series, between-series recovery duration and intensity); any of which has a likely effect on the acute physiological response. Manipulating HIT appropriately is important, not only with respect to the expected middle- to long-term physiological and performance adaptations, but also to maximize daily and/or weekly training periodization. Cardiopulmonary responses are typically the first variables to consider when programming HIT (refer to Part I). However, anaerobic glycolytic energy contribution and neuromuscular load should also be considered to maximize the training outcome. Contrasting HIT formats that elicit similar (and maximal) cardiorespiratory responses have been associated with distinctly different anaerobic energy contributions. The high locomotor speed/power requirements of HIT (i.e. ≥95 % of the minimal velocity/power that elicits maximal oxygen uptake [v/p(·)VO(2max)] to 100 % of maximal sprinting speed or power) and the accumulation of high-training volumes at high-exercise intensity (runners can cover up to 6-8 km at v(·)VO(2max) per session) can cause significant strain on the neuromuscular/musculoskeletal system. For athletes training twice a day, and/or in team sport players training a number of metabolic and neuromuscular systems within a weekly microcycle, this added physiological strain should be considered in light of the other physical and technical/tactical sessions, so as to avoid overload and optimize adaptation (i.e. maximize a given training stimulus and minimize musculoskeletal pain and/or injury risk). In this part of the review, the different aspects of HIT programming are discussed, from work/relief interval manipulation to HIT periodization, using different examples of training cycles from different sports, with continued reference to the cardiorespiratory adaptations outlined in Part I, as well as to anaerobic glycolytic contribution and neuromuscular/musculoskeletal load.

Changes of direction during high-intensity intermittent runs: neuromuscular and metabolic responses

BACKGROUND

The ability to sustain brief high-intensity intermittent efforts (HIE) is meant to be a major attribute for performance in team sports. Adding changes of direction to HIE is believed to increase the specificity of training drills with respect to game demands. The aim of this study was to investigate the influence of 90°-changes of direction (COD) during HIE on metabolic and neuromuscular responses.

METHODS

Eleven male, team sport players (30.5 ± 3.6 y) performed randomly HIE without (straight-line, 2×[10× 22 m]) or with (2×[10× ~16.5 m]) two 90°-COD. To account for the time lost while changing direction, the distance for COD runs during HIE was individually adjusted using the ratio between straight-line and COD sprints. Players also performed 2 countermovement (CMJ) and 2 drop (DJ) jumps, during and post HIE. Pulmonary oxygen uptake (VO2), quadriceps and hamstring oxygenation, blood lactate concentration (Δ[La]b), electromyography amplitude (RMS) of eight lower limb muscles and rating of perceived exertion (RPE) were measured for each condition.

RESULTS

During HIE, CODs had no substantial effects on changes in VO2, oxygenation, CMJ and DJ performance and RPE (all differences in the changes rated as unclear). Conversely, compared with straight-line runs, COD-runs were associated with a possibly higher Δ[La]b (+9.7 ± 10.4%, with chances for greater/similar/lower values of 57/42/0%) and either a lower (i.e., -11.9 ± 14.6%, 2/13/85 for semitendinosus and -8.5 ± 9.3%, 1/21/78 for lateral gastrocnemius) or equivalent decrease in electromyography amplitude.

CONCLUSION

Adding two 90°-CODs on adjusted distance during two sets of HIE is likely to elicit equivalent decreases in CMJ and DJ height, and similar cardiorespiratory and perceptual responses, despite a lower average running speed. A fatigue-induced modification in lower limb control observed with CODs may have elicited a selective reduction of electromyography activity in hamstring muscles and may induce, in turn, a potential mechanical loss of knee stability. Therefore, changing direction during HIE, with adjusted COD running distances, might be an effective training practice 1) to manipulate some components of the acute physiological load of HIE, 2) to promote long-term COD-specific neuromuscular adaptations aimed at improving performance and knee joint stability.

Validity of the modified 20-metre shuttle test: Assessment of cardiorespiratory fitness in people who have sustained a traumatic brain injury

PRIMARY OBJECTIVE

To validate the modified 20-metre shuttle test in adults who have sustained a traumatic brain injury (TBI).

DESIGN

Single-sample validity study.

SETTING

Brain injury rehabilitation unit.

PARTICIPANTS

Twenty-four adults with severe TBI, discharged from hospital for at least 6-months.

PROTOCOL

Participants attended the facility for a familiarization session, followed by a symptom-limited treadmill test and a modified shuttle test on two separate days. The treadmill test was based on an individualised protocol which used a physiotherapist-selected speed and increments in gradient every minute until volitional fatigue. The modified shuttle test was externally-paced and commenced with a speed of 2.4 km h(-1) which increased every minute until volitional fatigue.

MAIN MEASURES

Four primary measures were taken from both tests: peak oxygen uptake, peak heart rate, maximal velocity and rating of perceived exertion.

RESULTS

All participants completed the study. There were no adverse events. A high correlation was observed between the modified shuttle test and the treadmill test for peak oxygen uptake, peak heart rate and maximal velocity (r = 0.96, r = 0.80, r = 0.82, respectively; p < 0.001), but not for rating of perceived exertion (r = 0.013, p = 0.952).

CONCLUSION

The modified shuttle test is a valid measure of cardiorespiratory fitness in people who have sustained a TBI.

Prediction of VO2max from a new field test based on portable indirect calorimetry

We assessed the validity and reliability of the new 15m square shuttle run test (SST) for predicting laboratory treadmill test (TT) maximal oxygen uptake (VO(2 max)) compared to the 20 m multistage shuttle run test (MST) in 45 adult males. Thirty participants performed a TT and a SST once to develop a VO( 2max) prediction model. The remaining 15 participants performed the TT and MST once and the SST twice for cross-validation purposes. Throughout testing V O(2max) was determined via portable indirect calorimetry while blood lactate concentration was assessed at the fifth recovery minute. Comparisons of TT V O(2 max) (51.3+/-3.1 ml kg(-1)min(-1)) with SST measured (51.2+/-3.2 ml kg(-1)min(-1)) and predicted (50.9+/-3.3 ml kg(-1)min(-1)) V O(2 max) showed no differences while TT blood lactate was higher compared to SST (10.3+/-1.7 mmol vs. 9.7+/-1.7 mmol, respectively). In contrast, MST measured (53.4+/-3.5 ml kg(-1)min(-1)) and predicted (57.0+/-4.5 ml kg(-1)min(-1)) V O(2 max) and blood lactate (11.2+/-2.0 mmol) were significantly higher compared to TT. No test-retest differences were detected for SST measured and predicted V O(2 max) and blood lactate. It is concluded that the SST is a highly valid and reliable predictive test for V O(2 max).

Cardiorespiratory and cardiac autonomic responses to 30-15 intermittent fitness test in team sport players

The 30-15 Intermittent Fitness Test (30-15IFT) is an attractive alternative to classic continuous incremental field tests for defining a reference velocity for interval training prescription in team sport athletes. The aim of the present study was to compare cardiorespiratory and autonomic responses to 30-15IFT with those observed during a standard continuous test (CT). In 20 team sport players (20.9 +/- 2.2 years), cardiopulmonary parameters were measured during exercise and for 10 minutes after both tests. Final running velocity, peak lactate ([La]peak), and rating of perceived exertion (RPE) were also measured. Parasympathetic function was assessed during the postexercise recovery phase via heart rate (HR) recovery time constant (HRR[tau]) and HR variability (HRV) vagal-related indices. At exhaustion, no difference was observed in peak oxygen uptake VO2peak), respiratory exchange ratio, HR, or RPE between 30-15IFT and CT. In contrast, 30-15IFT led to significantly higher minute ventilation, [La]peak, and final velocity than CT (p < 0.05 for all parameters). All maximal cardiorespiratory variables observed during both tests were moderately to well correlated (e.g., r = 0.76, p = 0.001 for [latin capital VO2peak). Regarding ventilatory thresholds (VThs), all cardiorespiratory measurements were similar and well correlated between the 2 tests. Parasympathetic function was lower after 30-15IFT than after CT, as indicated by significantly longer HHR[tau] (81.9 +/- 18.2 vs. 60.5 +/- 19.5 for 30-15IFT and CT, respectively, p < 0.001) and lower HRV vagal-related indices (i.e., the root mean square of successive R-R intervals differences [rMSSD]: 4.1 +/- 2.4 and 7.0 +/- 4.9 milliseconds, p < 0.05). In conclusion, the 30-15IFT is accurate for assessing VThs and VO2peak, but it alters postexercise parasympathetic function more than a continuous incremental protocol.

The 30-15 intermittent fitness test: accuracy for individualizing interval training of young intermittent sport players

The objective of this study was to gather evidence supporting the accuracy of the 30-15 Intermittent Fitness Test (30-15IFT) for individualizing interval training of young intermittent sport players. In 59 young intermittent sport players (age, 16.2 +/- 2.3 years), we observed the relationships between the maximal running speed (MRS) reached at the end of the 30-15IFT (MRS30-15IFT) and physiological variables elicited by shuttle intermittent runs, including maximal oxygen uptake, explosive power of lower limbs, and the ability to repeat intense exercise bouts through cardiorespiratory recovery kinetics during exercise. To observe the capacity of the 30-15IFT to prescribe suitable running intensities for interval training sessions, we compared heart rates (HRs) reached during 3 series of intermittent runs, where distances were set according to the MRS30-15IFT and to MRS reached with 2 popular continuous field tests: the University of Montreal track test and the 20-m shuttle run test. The results show that the MRS30-15IFT is significantly correlated with all physiological variables elicited by shuttle intermittent runs (P < 0.05). Although mean HR were not different among the 3 series of intermittent runs, HR recorded during the runs based on MRS30-15IFT presented significantly less interindividual variation than when the continuously determined MRS were used as reference speeds. In conclusion, we can say that the 30-15IFT leads to an MRS that simultaneously takes into account various physiological qualities elicited when performing shuttle intermittent runs. For scheduling interval training sessions, the MRS30-15IFT appears to be an accurate reference speed for getting players with different physiological profiles to a similar level of cardiorespiratory demand and thus for standardizing training content.

Developmental coordination disorder and aerobic fitness: is it all in their heads or is measurement still the problem?

Developmental coordination disorder (DCD) is characterized by motor inproficiency, resulting in significant impairments in social and/or academic functioning. About 5-9% of all school-age children are affected. Previous research has shown that children with DCD have lower aerobic fitness levels than children without the disorder, although the reasons for this have not been tested in the literature. A potential explanation may lie in perceived adequacy regarding performance in physical activity. Although negative perceptions of adequacy in children with DCD likely reflect an accurate appraisal of actual physical abilities, aerobic fitness tests typically require minimal coordination skills. Children who perceive themselves to be less adequate are unlikely to persist at a task and may give up sooner on these tests of endurance. Using a large community based sample of children ages 9 through 14 (n=586), we examine whether differences in aerobic fitness (assessed by performance on a 20-m shuttle run test) between children who meet the criteria for DCD (n=44) and those who do not (n=542) is due to differences in perceived adequacy toward physical activity. Our results show that one-third of the effect of DCD on VO(2) can be attributed to differences in perceived adequacy. These results suggest that at least part of the reason children perform less well on tests of aerobic endurance is because they do not believe themselves to be as adequate as other children at physically active pursuits. The implications of this for further research are discussed.

Enhancing specificity in proxy-design for the assessment of bioenergetics

The purpose of this study was to examine the hypothesis that improved prediction of bioenergetics may be achieved when proxies are designed to simulate closely gold standard laboratory protocols. To accomplish this, a modified 'square' variation (SST) of the classical 20m Multistage Shuttle Run Test (MST) was designed aiming to reduce the stopping, turning and side-stepping manoeuvres. Within two weeks, 50 male volunteers (age 21.5+/-1.6, BMI 24.4+/-2.2) randomly underwent three maximal oxygen uptake (VO2max) assessments using a treadmill test (TT), the SST and MST. To assess SST reproducibility, 10 randomly-selected subjects performed the test twice. Validity results showed that mean predicted VO2max from SST was not significantly different compared to TT VO2max (p>0.05). In contrast, the equivalent value from MST was significantly higher (p<0.001) than TT. Furthermore, TT VO2max correlated with SST and MST at r=0.88 (p<0.001) and r=0.61 (p<0.05), respectively. The '95% limits of agreement' analysis (LIM(AG)) for SST and MST indicated a range of error equal to -0.5+/-5.4 and 8.1+/-8.0 (ml.kg(-1).min(-1)) with a coefficient of variation of +/-6 and +/-8.2%, respectively. Test-retest results for SST revealed no mean difference in VO2max (p>0.05) and a correlation coefficient of r=0.98 (p<0.001), while LIM(AG) demonstrated a range of error equal to -0.2+/-2.6 (ml.kg(-1).min(-1)) with a coefficient of variation of +/-5.6%. It is concluded that, compared to MST, the SST had a higher agreement with TT. The latter may well be explained by the closer simulation in bioenergetics between the two protocols (ie, the continuous nature of SST provides a closer proxy of TT).

Cardiorespiratory fitness and functional capacity assessed by the 20-meter shuttle walking test in patients with coronary artery disease

OBJECTIVE

To validate the 20-meter shuttle walking test (20MST) in the assessment of maximal oxygen consumption (VO(2)max) and maximal speed in patients with coronary artery disease (CAD).

DESIGN

Single-sample validity study.

SETTING

Cardiac rehabilitation service in France.

PARTICIPANTS

Seventeen men with CAD.

INTERVENTIONS

Subjects underwent a symptom-limited treadmill test (SLTT) in a laboratory, with a speed starting at 2.5km/h and increasing by 0.5km/h every minute, and performed an adapted 20MST in a corridor, with a speed starting at 3km/h and increasing by 1km/h every minute until exhaustion.

MAIN OUTCOME MEASURES

VO(2) measured during the 20MST with the Cosmed K2 telemetric gas analyzer (K2 VO(2)), estimated VO(2) calculated by the Léger equation (Léger VO(2)) from the maximal speed obtained during the 20MST, and VO(2) measured during the SLTT (SLTT VO(2)). Maximal speeds attained on the treadmill and on the 20MST were also compared.

RESULTS

A significant (P<.0001) difference was observed between the Léger estimate of VO(2) and those of K2 VO(2) and SLTT VO(2) (mean +/- standard deviation, 12.28+/-5.90mL. min(-1).kg(-1) vs 23.04+/-7.17 and 22.56+/-6.29mL.min(-1).kg(-1)). No difference was found between the treadmill and the 20MST maximal speeds (6.73+/-0.91km/h, 6.78+/-1.23km/h, respectively). Measured with the Cosmed K2, a significant relationship existed between VO(2) and each speed level (r=.95, P<.0001; VO(2)=4.24x speed-7.37, standard estimation error=2.29mL.min(-1).kg(-1)).

CONCLUSION

Maximal VO(2) and maximal speed measured on the treadmill did not differ significantly from those obtained on the 20MST. The current 20MST equation (Léger equation) was not valid to estimate VO(2) in CAD patients. A modified prediction equation of VO(2) was given and would need a larger number of patients to be generalized.

Association of maturation, sex, and body fat in cardiorespiratory fitness

The aims of this cross-sectional study were 1) to estimate changes in body composition and cardiorespiratory fitness across stages of pubertal maturation, and 2) to describe the relationship between maturity status and body fatness, regional fat distribution, and cardiorespiratory fitness. The sample consisted of 494 children (254 males, 240 females), 8-16 years of age. Height and weight were measured with standard anthropometric methods. Percentage of fat (%F) was estimated from two skinfold thicknesses and regional fat distribution was estimated by the ratio of the subscapular to the triceps skinfold (S/T ratio). Biological maturity was based on self-assessment of breast stages in females and pubic hair stages in males. A maximal multistage 20-m shuttle run was used to predict maximal aerobic capacity from maximal aerobic speed. Both VO(2)max and 20SRT-time were used as indicators of cardiorespiratory fitness. ANCOVA with age as the covariate was used. There were significant differences among girls across pubertal stages. Among boys, only weight and height differed significantly by stage of maturity. When adjusted for maturity status, cardiorespiratory fitness expressed either as VO(2)/kg body mass or 20SRT-time was inversely associated with %F in both sexes. This suggests that sexual maturity status alone accounts for a small portion of the variance in aerobic fitness. Height, %F and the S/T ratio were also significantly associated with VO(2)/kg body mass and 20SRT-time.

Maturação, composição corporal e aptidão cardiorrespiratória em crianças e adolescentes na área do grande Porto, Portugal

OBJETIVOS: determinar, em escolares portugueses de oito a 16 anos (256 do sexo masculino e 268 do sexo feminino): os padrões de mudanças na composição corporal e no VO2máx; a relação entre o percentual de massa gorda (%MG), índice de massa corporal (IMC) e o somatório de dobras de adiposidade subcutânea (SSKF) com o VO2máx; a percentagem de obesos. MÉTODOS: o percentual de massa gorda foi estimado do SSKF (subescapular e tricipital). A amostra foi subdividida em estágios maturacionais de Tanner. A aptidão cardiorrespiratória foi avaliada através do teste Shutlle-run de 20 metros. RESULTADOS: as variáveis antropométricas e o percentual de massa gorda estiveram de acordo com dados já publicados. Os rapazes apresentaram VO2máx mais elevado (p < 0,05) do que as moças na maioria dos estágios. Correlações negativas, moderadas e significativas (p < 0,05) entre o percentual de massa gorda o VO2máx foram obtidas em ambos os sexos, em todos os estágios. Na análise dos três indicadores de obesidade (IMC, %MG e SSKF), 11,2% dos rapazes e 14,3% das moças apresentaram valores acima dos padrões normativos. CONCLUSES: padrões normais de crescimento foram verificados em ambos os sexos. Crianças que apresentaram menor VO2máx também apresentaram maior percentual de massa gorda. Ambos os sexos apresentaram valores sugerindo excesso de gordura corporal no início da adolescência.