Peripheral muscle function during repeated changes of direction in professional soccer players.

PURPOSES: To evaluate peripheral muscle function of the knee extensors during repeated changes of direction in professional soccer players by examining differences between competitive levels, periods of the season and playing positions, and to investigate the relationships between peripheral muscle function and physical activities during matches. METHODS: Knee extensor peripheral muscle function (twitch peak torque, PT) of 593 male soccer players from 13 European professional clubs competing at 3 different levels was evaluated 4 times during the season. The main outcomes were PTmax (maximal PT, muscle contractility), MPmax (maximal metabolic power exercise intensity) and PTdec (PT decline, muscle fatigability) obtained during intermittent runs of increasing intensity with multiple changes of direction interspersed with electrically evoked contractions. Relative total and sprint distances covered during a whole match and during short intervals were quantified from a sub-sample. RESULTS: PTmax and MPmax were higher for first than for second division (p < 0.047; d = 0.15-0.23) and Under-19 players (p < 0.007; d = 0.17-0.25). MPmax was lower (p < 0.016; d = 0.23-0.32) and PTdec was higher (p < 0.004; d = 0.26-0.39) in the pre-season compared to all the other time points. MPmax was higher for fullbacks than attackers and defenders (p < 0.041; d = 0.20-0.22). PTdec was higher for defenders than fullbacks, midfielders and wings (p < 0.029; d = 0.21-0.28). PTmax was associated with whole-match relative total distance (p = 0.004; d = 0.26). PTdec was associated with whole-match relative total distance and relative short-interval sprint distance (p < 0.050; d = 0.18-0.22). CONCLUSION: The ability to sustain repeated change of direction efforts at high intensities while preserving peripheral muscle function should be considered an important determinant of soccer physical performance.

Impact of COVID-19 Lockdown on Serie A Soccer Players' Physical Qualities.

In March 2020, the COVID-19 pandemic forced most activities in Italy, including soccer, to cease. During lockdown, players could only train at home, with limited evidence regarding the effect of this period. Therefore, this study aimed to investigate the effect of COVID-19 lockdown on professional soccer players' physical performance. Aerobic fitness and vertical jump were assessed before and after four periods in two different seasons: COVID-19 lockdown, competitive period before lockdown, competitive period and summer break of the 2016-2017 season. Linear mixed models were used to examine within-period changes and between-period differences in changes observed during COVID-19 lockdown and the three other periods. Within-period changes in aerobic fitness showed a significant improvement following COVID-19 lockdown (p<0.001) and a significant decline during summer break (p<0.001). Between-period differences were significant in the comparison of COVID-19 lockdown with both the competitive 2019-2020 season (p<0.01) and summer break (p<0.001). For the vertical jump, only the between-period comparison revealed significant differences as the changes associated with COVID-19 lockdown were worse than those of the two competitive periods, for both absolute (p<0.05; p<0.001) and relative peak power (p<0.01; p<0.001). Home-based training during lockdown was effective to improve aerobic fitness, although it did not allow players to maintain their competitive period's power levels.

Impact of COVID-19 lockdown on professional soccer players' match physical activities.

AIM: The COVID-19 pandemic forced the 2019-20 Italian Serie A competition to stop and players went into lockdown. During lockdown, players only trained at home, likely having a detrimental effect on players' physical fitness and capacity. This study investigated the effect of the COVID-19 lockdown on professional soccer players' match physical activities. METHODS: Match activities of 265 male professional soccer players were assessed in two periods prior to (PRE1 and PRE2) and one period following the lockdown (POST) using a video tracking system. Linear mixed models were used to examine differences between-periods in total (TD), very high-speed (VHS), sprint (SPR), high-acceleration (ACC) and high-deceleration (DEC) distances, considering full match data and data from six 15-min intervals. RESULTS: TD and VHS during POST were lower than the two other competitive periods (p < 0.001, d small-moderate). SPR did not show differences between periods (p > 0.636). ACC and DEC during POST were lower than PRE2 (p < 0.015, d small). Declines in most 15-min intervals after lockdown were observed in TD and VHS. CONCLUSIONS: There were small differences in the temporal distribution of SPR, ACC and DEC at POST. After the COVID-19 lockdown, soccer players' higher-intensity running activities were similar to those of games played before the lockdown, but TD and VHS decreased, both considering the entire match and 15-min intervals. The temporal distribution of running activities was mostly stable throughout the season.

[The effects of a clinical therapeutic intervention in pain assessment and management in surgical ICU patients: a before-and-after intervention study on pain intensity and use of analgesia]. / Gli effetti di un intervento clinico organizzativo sulla valutazione e gestione del dolore postoperatorio in terapia intensiva: studio before-after sull'intensità di dolore e uso dell'analgesia.

AIMS: the aims of this study were to test the efficacy of a training program in order to reduce pain intensity in surgical ICU patients and improving postoperative pain assessment and management. METHODS: longitudinal, before and after experimental study. A total of 261 patients, 126 in Group A (before intervention) and 135 in Group B (after intervention) were included. Data were collected prospectively before and after a training intervention and the implementation of a pain management protocol. RESULTS: a significant reduction was observed in pain intensity scores collected at 6 hours (p=.016) 12 hours (p -.001) and 48 hours (p=.005) postoperatively. Intense pain was most observed in Group A than Group B (RR=1.98; 95% CI= 1.05-3.71, p=.0302). A significantly smaller proportion of patients treated after intervention received morphine (p=.036) and propofol (p=.045). Although there has been no increase in pain assessments, the interval (hours/minutes) between drugs administrations was reduced (Group A 6.35 +1.19 vs Group B 6.21 +0.5) (p=.006). Mechanical ventilation lasted longer in Group A (3.67 days + 6.6 vs 2.44 days + 4.45) (MD = 1.23; 95% CI= -0.1541- 2.6141) (p=.0415). CONCLUSION: the implementation of the organizational changes on pain prevention in this ICU, using standardized education, led to less pain in surgical ICU patients. However further randomized studies and with larger patient samples are needed.

The cost of running on natural grass and artificial turf surfaces.

The purpose of this study was to evaluate the metabolic cost of running (Cr) on natural grass (NG) and artificial turf (AT), compared with a hard surface (HS), that is, asphalted track. Eight amateur soccer players (mean ± SD: age 22.9 ± 2.3 years, body mass 69.0 ± 4.7 kg, and height 178 ± 5 cm) completed 9 runs (3 surfaces × 3 speeds, i.e., 2.22, 2.78, 3.33 m·s) of 6 minutes, in a random order on the different surfaces. Characteristics of the running surfaces were assessed at 3 points of each running track by measuring shock absorption and standard vertical deformation, via an 'artificial athlete' device according to FIFA protocol. No significant interactions (2-way ANOVA analysis; p = 0.38) were found between running surfaces and running speeds. A significant main effect for surface was found. The average Cr values were 4.02 ± 0.25 J·kg·L·m on HS, 4.22 ± 0.35 J·kg·L·m on NG, and 4.21 ± 0.31 J·kg·L·m on AT. The Cr was also higher at 3.33 m·s compared with the Cr measured at the other 2 running speeds. In conclusion, we found a Cr of ∼ 4.20 J·kg·L·m on both natural and artificial grass football pitches, in accordance with similar percentage shock absorption characteristics of these 2 tested surfaces. Our finding allows a better computation of the Cr on NG and AT, and supports the exclusion of the Cr as a potential factor for the higher physical effort in matches played on artificial turf, as reported by soccer players.