Search Results

You are looking at 1 - 2 of 2 items for :

  • Author: Sergio Domínguez-Cobo x
  • Physical Education and Coaching x
  • International Journal of Sports Physiology and Performance x
  • Sport and Exercise Science/Kinesiology x
  • Refine by Access: All Content x
Clear All Modify Search
Restricted access

Two New Indexes for the Assessment of Autonomic Balance in Elite Soccer Players

José Naranjo Orellana, Blanca de la Cruz Torres, Elena Sarabia Cachadiña, Moisés de Hoyo, and Sergio Domínguez Cobo

Purpose:

The application of Poincaré-plot analysis to heart-rate variability (HRV) is a common method for the assessment of autonomic balance. However, results obtained from the indexes provided by this analysis tend to be difficult to interpret. In this study the authors aimed to prove the usefulness of 2 new indexes: the stress score (SS) and the sympathetic:parasympathetic ratio (S:PS ratio).

Methods:

25 professional Spanish soccer players from same team underwent 330 resting measurements of HRV. All subjects experienced 10 min of HRV monitoring through an R-R-interval recorder. The following parameters were calculated: (1) Poincaré-plot indexes: SD1 (transverse axis), which is proportional to parasympathetic activity; SD2 (longitudinal axis), which is inversely proportional to sympathetic activity; and the SD1:SD2 ratio; (2) time-domain parameters: standard deviation of R-R intervals (SDNN), root-mean-square differences of successive heartbeat intervals (rMSSD), and percentage of successive R-R-interval pairs differing in more than 50 ms in the entire recording divided by the total number of R-R intervals (pNN50); and (3) the proposed 2 new indexes: the SS and the S:PS ratio.

Results:

The study found a high negative correlation between the SS and SDNN (R 2 = .94). The S:PS ratio correlated inversely to rMSSD (R 2 = .95), SDNN (R 2 = .94), and pNN50 (R 2 = .74). The S:PS ratio showed a strong correlation with SD1 (R 2 = .95) and SS (r = .87, R 2 = .88).

Conclusions:

The application of the SS as sympathetic-activity index and the S:PS ratio as a representation of autonomic balance (SS:SD1) provides a better understanding of the Poincaré-plot method in HRV.

Restricted access

Effects of a 10-Week In-Season Eccentric-Overload Training Program on Muscle-Injury Prevention and Performance in Junior Elite Soccer Players

Moisés de Hoyo, Marco Pozzo, Borja Sañudo, Luis Carrasco, Oliver Gonzalo-Skok, Sergio Domínguez-Cobo, and Eduardo Morán-Camacho

Purpose:

To analyze the effect of an eccentric-overload training program (ie, half-squat and leg-curl exercises using flywheel ergometers) with individualized load on muscle-injury incidence and severity and performance in junior elite soccer players.

Methods:

Thirty-six young players (U-17 to U-19) were recruited and assigned to an experimental (EXP) or control group (CON). The training program consisted of 1 or 2 sessions/wk (3–6 sets with 6 repetitions) during 10 wk. The outcome measured included muscle injury (incidence per 1000 h of exposure and injury severity) and performance tests (countermovement jump [CMJ], 10-m and 20-m sprint test).

Results:

Between-groups results showed a likely (ES: 0.94) lower number of days of absence per injury and a possible decrement of incidence per 1000 h of match play in EXP than in CON. Regarding muscle performance, a substantial better improvement (likely to very likely) was found in 20-m sprint time (ES: 0.37), 10-m flying-sprint time (ES: 0.77), and CMJ (ES: 0.79) for EXP than for CON. Within-group analysis showed an unclear effect in each variable in CON. Conversely, substantial improvements were obtained in CMJ (ES: 0.58), 20-m sprint time (ES: 0.32), 10-m flying-sprint time (ES: 0.95), and injury severity (ES: 0.59) in EXP. Furthermore, a possible decrement in total injury incidence was also reported in EXP.

Conclusions:

The eccentric-based program led to a reduction in muscle-injury incidence and severity and showed improvements in common soccer tasks such as jumping ability and linear-sprinting speed.