Author(s): PANASCI, M., FERRANDO, V., CASTAGNA, C., APOLLARO, G., RUGGERI, P., FAELLI, E. , Institution: UNIVERSITY OF GENOA, Country: ITALY, Abstract-ID: 866

INTRODUCTION:
This study examined the relationship between physiological and performance responses obtained in the Fitness Intermittent Test 45-15 (FIT 45-15) and in Yo-Yo Intermittent Recovery test level 1 (YYIR1) with internal and external load outcomes measured during official matches in U19 female football players.
METHODS:
15 female football players were recruited from a professional club. The experimental protocol included 4 testing sessions conducted over a one-month period, with 1 session per week. Each endurance test (FIT 45-15 and YYIR1) was administered twice. Subsequently, players’ physical demands were monitored during 6 official age-category matches. Test outcomes included: maximal oxygen uptake (VO₂max), maximal heart rate (HRmax) as well as maximal aerobic speed (MAS 45-15) recorded in FIT 45-15 and total distance covered in YYIR1 (YYIR1 distance). VO₂max was directly assessed during FIT 45-15 by a portable metabolic system (Cosmed K5) and estimated in YYIR1 using this formula: YYIR1 distance (m)×0.0084+6.40. During official matches, the following external load parameters, measured by a 50Hz GPS, were considered: total distance (TD), high-speed running distance (HSR; 14.4-19.8 km/h), very high-speed running distance (VHSR; 19.8-25.2 km/h), acceleration (ACC; ≥3 m/s²) and deceleration (DEC; ≤-3 m/s²) distances. Moreover, HR, recorded via a heart-rate monitor (Polar H10), was selected as internal load outcome. To identify internal load distribution, HR was divided into 5 intensity zones: <50% HRmax (low), 50-70% (moderate), 70-80% (sub-high), 80-90% (high), and >90% (maximal intensity).
RESULTS:
In FIT 45-15, VO₂max showed large to very large correlations with most external (i.e., HRS, VHSR, and ACC; Pearson’s correlation coefficient (r) = 0.626-0.897, p<0.01) and internal (i.e., 50-70%, 80-90%, and >90% HRmax; r = -0.620-0.880, p < 0.01) load outcomes while HRmax presented a large correlation only with DEC (r = -0.597, p<0.05). MAS 45-15 revealed large correlations with most external load parameters (i.e., HRS, VHSR and ACC; r = 0.562-0.619, p<0.05) and some HR intensity zones (i.e., 50-70% and 70-80% HRmax; r = -0.537-0.575, p<0.05). In YYIR1, estimated VO₂max and YYIR1 distance showed large to nearly perfect correlations with most external (i.e., HRS, VHSR and ACC; r = 0.678-0.947, p<0.01) and internal (i.e., 50-70%, 80-90% and >90% HRmax; r = -0.645-0.830, p<0.01) load outcomes, whereas HRmax presented no significant correlation (p>0.05) with both external and internal load parameters.
CONCLUSION:
Our findings indicate that both the FIT 45-15 and YYIR1 demonstrated similar correlation patterns with match demands in Under-19 Female Football players, supporting their use in monitoring endurance-related high-intensity capacity in those players. However, the YYIR1 responses revealed higher relationships with official match external load measures than the FIT 45-15, thus indicating its greater utility for monitoring training and match demands in this population.