Neuromuscular Responses to Conditioned Soccer Sessions Assessed Via GPS-Embedded Accelerometers: Insights Into Tactical Periodization

Buchheit, M., Lacome, M., Cholley, Y., Simpson, B.M.

Purpose: To 1) examine the reliability of field-based running-specific measures of neuromuscular function
assessed via GPS-embedded accelerometers and 2) examine their responses to three typical conditioned
sessions (i.e., Strength, Endurance and Speed) in elite soccer players. Methods: Before and immediately
after each session, vertical jump (CMJ) and adductors squeeze strength (Groin) performances were
recorded. Players also performed a 4-min run at 12 km/h followed by 4 ~60-m runs (run =12 s, r =33 s).
GPS (15-Hz) and accelerometer (100 Hz) data collected during the four runs + the recovery periods
excluding the last recovery period were used to derive vertical stiffness (K), peak loading force (peak force
over all the foot-strikes, Fpeak) and propulsion efficiency (i.e., ratio between velocity and force loads,
Vl/Fl). Results: Typical errors were small (CMJ, Groin, K and Vl/Fl) and moderate (Fpeak), with moderate
(Fpeak), high (K and Vl/Fl) and very high ICC (CMJ and Groin). After all sessions, there were small
decreases in Groin and increases in K, while changes in F were all unclear. In contrast, the CMJ and Vl/Fl
ratio responses were session-dependent: small increase in CMJ after Speed and Endurance, but unclear
changes after Strength; the Vl/Fl ratio increased largely after Strength, while there was a small and a
moderate decrease after the Endurance and Speed, respectively. Conclusions: Running-specific
measures of neuromuscular function assessed in the field via GPS-embedded accelerometers show
acceptable levels of reliability. While the three sessions examined may be associated with limited
neuromuscular fatigue, changes in neuromuscular performance and propulsion-efficiency are
likely session objective-dependent.