Reliability of Submaximal Yo-Yo Tests in 9- to 16-Year-Old Untrained Schoolchildren

Essential Improvements in Fat Percentage and Cardiometabolic Fitness After a Residential Stay for Socially Vulnerable Children-With and Without the "11 for Health" Concept

The Danish Christmas Seal Homes offer a 10-week residential stay for socially vulnerable children. We aimed to examine the effects on body composition and cardiometabolic fitness variables of the standard program (SG) and whether substituting physical activity sessions with sessions from a football-based health education program is beneficial for the participants ("11 for Health"; SG+). Three hundred and nine children participated in SG (12.4 [1.6] y) and 305 in SG+ (12.4 [1.4] y). Fat percentage was lowered by 6% for females (from 37% to 31%) and 8% for males (from 36% to 28%), with no between-group differences. We observed improvements in systolic and diastolic blood pressure (3 and 5 mm Hg, respectively), resting heart rate (10 beats/min), aerobic fitness, jump performance, and relative muscle mass with no between-group differences. Furthermore, there were between-group differences in insulin levels for females (1.7 pmol/L; 95% CI, 0.3 to 3.0) and postural balance for males (1.0 s; 95% CI, 0.0 to 2.0), both in favor of SG+, and covered distance in the Andersen test for females (26 m; 95% CI, 3 to 49) in favor of SG. In conclusion, a 10-week stay at the Danish Christmas Seal Home resulted in clinically relevant improvement in fat percentage and cardiometabolic fitness in socially vulnerable children, regardless of the program type.

A 10-week implementation of the FIT FIRST FOR ALL school-based physical activity concept effectively improves cardiorespiratory fitness and body composition in 7-16-year-old schoolchildren

Introduction

The purpose of the present study was to investigate the impact of the FIT FIRST FOR ALL school-based physical activity program on health-related physical fitness in Faroese schoolchildren. The program aimed to add three weekly sessions of organized high-intensity physical activity to the standard weekly physical education sessions for all pupils across the entire school.

Methods

A non-randomized controlled design was used to evaluate the effects of the program. Two schools participated, including one intervention school (INT; n =179) and one control school (CON; n =181), with pupils aged 7-16 years (grades 1-9). The FIT FIRST FOR ALL program consisted of three weekly 40-minute sessions of age-adjusted high-intensity physical activity over 10 weeks for the INT school, while the CON school continued their normal school program. Pre- and post-intervention assessments included cardiorespiratory fitness (Yo-Yo IR1C test), agility (Arrowhead Agility test), postural balance (Stork Stand), standing long jump performance, body composition, blood pressure, and resting heart rate.

Results

A significant time × group effect (p < 0.001) was observed for cardiorespiratory fitness, which increased by 31% [23;39] in INT (p < 0.001) and remained unaltered in CON (7% [-2;16], p = 0.13). In addition, a time × group effect (p < 0.001) was observed for agility, which improved by 2.1% [1.0;3.2] in INT (p < 0.001) and regressed by 3.3% [2.3;4.4] in CON (p < 0.001). No significant between-group effects were found for standing long jump and balance. A time × group effect (p < 0.001) was observed for changes in total muscle mass, which increased by 1.4 kg [1.2;1.5] in INT (p < 0.001) and by 0.4 kg [0.3;0.6] in CON (p < 0.05). Furthermore, a time × group effect (p < 0.001) was observed for total fat percentage, which decreased by -2.3% [-2.8;-1.9] in INT (p < 0.001) and remained unchanged in CON (-0.3% [-0.7;0.1], p = 0.16). No significant time × group effects were found for blood pressure and resting heart rate.

Discussion

The FIT FIRST FOR ALL program significantly improved cardiorespiratory fitness and agility, and it led to favorable changes in body composition in the intervention school. These findings suggest that the program is highly effective in enhancing physical fitness and health status across all investigated age groups when implemented at a school-wide level.

Estimation of maximal oxygen uptake using the heart rate ratio method in male recreational football players

Maximal oxygen uptake (VO_2max) is associated with cardiovascular and metabolic health in the general population. The heart rate (HR) ratio method (HR_ratio) is a valid, easy and accessible method for estimating VO_2max in well-trained subjects. This study examined the validity of using the HR_ratio to estimate VO_2max in recreational football players in the untrained and trained states. Sixty-six participants (age 39.3 ± 5.8 years) were tested pre-training and 28 after 12 weeks, for VO_2max assessment, running on a treadmill alternating speed (1 km h⁻¹) and inclination (1%) increments every 30 s until exhaustion. Maximal HR (HR_max) was assessed directly with a multiple approach and estimated with selected equations. Resting HR (HR_rest) was measured in supine position, after 15 min of rest. The HR_ratio method considers the product of HR_max/HR_rest ratio by a theoretical proportionality factor (15 ml kg⁻¹ min⁻¹, TPF) to estimate VO_2max. This population-specific proportionality factor (SPF) was 14.6 ± 2.6 ml kg⁻¹ min⁻¹. In the untrained state (n = 66), participants’ actual VO_2max (41.3 ± 6.2 ml kg⁻¹ min⁻¹) was moderately lower (~ 2 ml kg⁻¹ min⁻¹) than the estimated VO_2max using the TPF. A nonsignificant difference (0.7 ml kg⁻¹ min⁻¹) was found when the VO_2max was estimated using the SPF. When using HR_max equations and the TPF, a small nonsignificant difference (~ 1.5 ml kg⁻¹ min⁻¹) was reported between actual and estimated VO_2max. In the trained state (n = 28), the estimated VO_2max values were not significantly different from the actual VO_2max (44.2 ± 5.2 ml kg⁻¹ min⁻¹), with large effect sizes when considering TPF and estimated HR_max. The results of this study provide evidence of the applicability of HR_ratio in estimating VO_2max in male adult/middle-aged recreational football players.

Effekte von hochintensivem Intervalltraining (HIIT) auf Body-Mass-Index (BMI) und Körperfettanteil von übergewichtigen und adipösen Kindern – eine systematische Übersichtsarbeit

Hintergrund Mehr als 340 Millionen Kinder gelten weltweit als übergewichtig oder adipös, ihre Anzahl nahm in den letzten Jahren – auch durch die Coronapandemie – erheblich zu. Eine alternative Behandlung zur Reduzierung des Übergewichts, die in den Empfehlungen bisher keine große Beachtung findet, stellt das sogenannte hochintensive Intervalltraining (HIIT) dar.

Ziel Darstellung der Wirksamkeit von hochintensivem Intervalltraining auf den BMI und Körperfettanteil übergewichtiger und adipöser Kinder im Alter von 6–13 Jahren.

Methode Die Erstellung der systematischen Übersichtsarbeit orientierte sich an den PRISMA-Guidelines. Für die Literaturrecherche wurden die Datenbanken MEDLINE, Cochrane Library, CINAHL, Embase, Sports Medicine & Education Index und Web of Science nach Studien mit hochintensivem Intervalltraining für übergewichtige und adipöse Kinder durchsucht. Die Bewertung der methodischen Studienqualität erfolgte mittels PEDro-Skala, MINORS und Risk of Bias. Die Berichtsqualität wurde anhand von CONSORT und TREND bewertet.

Ergebnisse Es wurden 6 randomisierte kontrollierte Studien und 2 kontrollierte klinische Studien mit 479 HIIT-Teilnehmenden betrachtet. Diese zeigten, dass hochintensives Intervalltraining positive Auswirkungen auf den BMI und Körperfettanteil übergewichtiger und adipöser Kinder hat.

Schlussfolgerung Hochintensives Intervalltraining ist eine kinderfreundliche und zugleich effektive Alternative zur Behandlung von übergewichtigen und adipösen Kindern. Weitere klinische Studien sind erforderlich, um die Ergebnisse zu bekräftigen.

Yo-Yo intermittent tests are a valid tool for aerobic fitness assessment in recreational football

PURPOSE

To examine the suitability of three versions and two levels of the Yo-Yo intermittent tests for assessing and tracking aerobic fitness status development in male recreational football players. Sixty-six untrained participants (age 39 ± 6 years, VO2max 41.2 ± 6.2 ml kg-1 min-1, body mass 81.9 ± 10.8 kg, height 173.2 ± 6.4 cm) partook in a 12-week recreational football training program. They were evaluated during the Yo-Yo intermittent endurance level 1 (YYIE1) and 2 (YYIE2) tests and the Yo-Yo intermittent recovery level 1 test (YYIR1), and during a treadmill test for VO2max assessment, at baseline. Thirty-two out of these 66 participants replicated all these tests at post-intervention. An additional group of 30 male age-matched recreational football players that afterwards started the 12-week recreational football program (age 39 ± 6 years, VO2max 45.3 ± 5.8 ml kg-1 min-1, body mass 82.5 ± 7.8 kg, height 172.8 ± 5.4 cm) was evaluated at baseline to test cross-validation.

RESULTS

The Yo-Yo tests showed very large associations with VO2max at baseline (r = 0.75-0.77; P < 0.0001) and at post-intervention (r = 0.76-0.82; P < 0.0005). Post-training, very large associations were found between YYIE2 performance and VO2max (r = 0.65, P < 0.0001). Cross-validation revealed small to large differences between the observed and estimated VO2max values (1.5-2.96 ml kg-1 min-1) with moderate typical error of estimation (7.9-8.7%) across the tests. Performance in the YYIE1, YYIE2 and YYIR1 tests of ≥ 1760, 480 and 600 m, respectively, indicated good to excellent VO2max values.

CONCLUSIONS

The Yo-Yo tests considered here showed robust and consistent criterion validity. The YYIE2 could be a more accurate option to track aerobic fitness development in recreational football players.

Submaximal field testing validity for aerobic fitness assessment in recreational football

Submaximal field tests are especially recommended when repeated testing is warranted. This study aimed at assessing the validity of the submaximal versions of the Yo-Yo intermittent tests in male recreational football players in untrained and trained status. The participants' (n = 66; age 39.3 ± 5.8 years, VO_2max 41.2 ± 6.2 mL·kg^-1 ·min^-1 , body mass 81.9 ± 10.8 kg, height 173.2 ± 6.4 cm) heart rate after 2 minutes (HR_2min ) during the level 1 (YYIE1_HR2min ) and 2 (YYIE2_HR2min ) versions of the Yo-Yo intermittent endurance test and the level 1 version of the Yo-Yo intermittent recovery test (YYIR1_HR2min ) was plotted against individual VO_2max values. Thirty-two participants performed all the tests after a 12-week recreational football intervention for test responsiveness. Associations between VO_2max and YYIE1_HR2min were large to small (P = .0001). Large to trivial associations were found between YYIE2_HR2min , YYIR1_HR2min , and VO_2max (P < .01). Maximal Yo-Yo performances were large, significant, and inversely related to HR_2min (-0.68 to -0.49, P < .0001). Pre- to post-intervention ICC values were good for YYIE1_HR2min and YYIE2_HR2min , and excellent for YYIR1_HR2min . Post-intervention associations between HR_2min and Yo-Yo maximal performances were large to very large (-0.55 to -0.72; P < .002, n = 32). Training-induced changes in VO_2max moderately correlated with YYIR1_HR2min (-0.48; P = .007; n = 32). HR_2min lower than 89%, 98%, and 91% HR_max for YYIE1_HR2min , YYIE2_HR2min , and YYIR1_HR2min , respectively, may be considered as signs of good to excellent VO_2max levels. Since in the YYIE1_HR2min , the participants attained 84% HR_max and test specificity increased for HR_2min values <89%, this test may be the preferred choice when repeated assessment of aerobic fitness, using submaximal intermittent Yo-Yo tests, is considered in recreational football.