The French Contrast Method

WHAT IS THE FCM?

     The French Contrast Method (FMC) is an effective and less time-consuming strategy to improve physical performance, that is currently applied in sports that require high levels of force and neuromuscular power (Dietz & Peterson, 2012; Hernandez-Preciado et al., 2018). The FCM was originally developed by the Track & Field coach Gilles Cometti and consists of combining Complex and Contrast training methods in four consecutive exercises: a resistance exercise performed at a near maximal load, a plyometric exercise that mimics the same movement pattern, a resistance exercise trying to maximize the power production and, lastly, a plyometric or accelerated plyometric exercise (Dietz & Peterson, 2012). The FCM is a specialized method for specific season periods which pushes the physiological response of the athlete further and forces the utilization of alactic or anaerobic capacity to increase physical performance and develop gains in explosive performance (Dietz & Peterson, 2012).

HOW DO YOU PERFORM THE FCM?

EXERCISE 1 (STRENGHT)

     During the FCM, performing a heavy resistance exercise (>85% 1-RM) aims to increase the excitability of the central nervous system, and to produce a higher muscle contractile performance prior to a biomechanically similar explosive exercise (Dietz & Peterson, 2012). Previous research provides evidence to support the implementation of overcoming isometric maximal voluntary contractions (MVCs) to provide a greater potentiation (Rixon, Lamont, & Bemben, 2007). For example, performing isometric MVCs (3 sets of 3 seconds) induces a greater potentiation than 1 set of a dynamic back squat at 90% 1-RM (Rixon et al., 2007). Interestingly, due to its static character, isometric MVCs with short muscle lengths (knee joint at 165º) is an important determinant to induce acute improvement in vertical jump performance (Tsoukos, Bogdanis, Terzis, & Veligekas, 2016). Furthermore, it has been shown that overcoming isometrics at a knee angle of 90º (long muscle length) produce higher levels of fatigue than at a shorter muscle length, such as 165º (Tsoukos et al., 2016). It is also well documented that isometric muscle contractions improve muscle stiffness (Burgess et al., 2007; Kubo et a., 2012). These adaptations are attributed to architectural alignment within the fibres in the tendon and allow to rapidly transfer force through the Stretch Shortening Cycle (SSC), a critical skill in sprint acceleration and Change of Direction Speed (CODS). Therefore, the immediate performance of a similar movement pattern following the isometric MVCs may enhance the transfer of the training (Verkhoshansky & Verkhoshansky, 2011).

EXERCISE 2 (PLYOMETRICS)

     The performance of plyometrics has been suggested as an important exercise to increase lower-body explosive strength (Asadi et al., 2016). Plyometric exercises involve jumping, hopping or skipping, and have a strong correlation with most common movements in many sports (e.g. basketball) as involves the application of the SSC (Saez-de-Villarreal, Requena, & Cronin, 2012; Asadi et al., 2016). Plyometrics involve a lengthening (eccentric contraction) of the muscle-tendon unit that is immediately followed by a shortening or concentric contraction, known as the SSC (Wilson & Flanagan, 2008). The SSC enhances the ability of the muscle tendon unit to produce maximal force in the shortest time period, through a greater stiffness (Maloney & Fletcher, 2018). Higher stiffness may improve neuromuscular performance during sprinting (Lopez-Mangini & Fabrica, 2016) or a COD (Serpell et al., 2014). Furthermore, the force-vector theory has recently highlighted the importance of applying the force in the desired direction (i.e. vertical, horizontal, lateral), to reach a physical performance improvement rather than just increasing the ground reaction forces (Contreras et al., 2017; Gonzalo-Skok et al., 2017). Thus, plyometrics training with a horizontal force application is an effective way to improve sprinting and CODS (Asadi et al., 2016; Gonzalo-Skok et al., 2018)

EXERCISE 3 (SPEED-STRENGTH)

     Once the plyometric exercise is completed, the athlete starts another resistance exercise to maximize the power production in the desired direction. It is during this exercise when the athlete develops explosive work capacity in a fatigued state (Dietz & Peterson, 2012). A primarily objective to improve acceleration performance is to optimize the GRF vector facilitating a horizontal propulsive orientation (Morin et al., 2011). Thus, athletes often train with resisted sprint through the performance of heavy sled towing (HST) (Petrakos, Morin, & Egan, 2015). Although sprint adaptations may be velocity specific to the loads applied (Petrakos et al., 2015), training with heavy loaded sleds [>30% body mass (BM)] leads the athlete to run in a more inclined horizontally-oriented position. Therefore, the athlete runs slower producing more horizontal force to the ground and reduces the mean vertical ground reaction forces (Jarvis, Turner, Chavda, & Bishop, 2017). Moreover, HST is an effective exercise to improve sprint, because it leads to similar neuromuscular adaptations to those required for improving sprint acceleration performance (Kawamori, Newton, & Nosaka, 2014). Research exploring the acute effects of HST (30%, 50% & 75% BM) has shown that it can potentiate acceleration over 0 – 15 metres (Jarvis et al., 2017; Wong et al., 2017) and subsequent sprint performance (Winwood, Posthumus, Cronin, & Keogh, 2016).

EXERCISE 4 (ASSISTED PLYOMETRICS)

     The FCM concludes with an accelerated or overspeed plyometric exercise. To improve neuromuscular power, we need both strength-dominant and speed-dominant exercises; thus, it is important to span the entire spectrum of the force–velocity continuum (Young, Talpey, Feros, O’Grady, & Radford, 2015b). For example, when sprinting the horizontal velocity of the body reaches 4 metres per second (m/s) within the first 5 metres, and increase to 6.8 m/s between 5 – 10 metres (Lockie, Murphy, Schultz, Knight, & Janse de Jonge, 2012). Furthermore, GCT are relatively short since the first step (0.21 seconds) and every step is getting shorter (Wild, Bezodis, Blagrove, & Bezodis, 2011); therefore, rapid SSC through the leg extensors is crucial in order to improve the performance. Regarding the force–velocity relationship, the speed of power exercises is relatively slow (2 – 4 m/s). Research indicates that even peak velocities of jump squats performed at maximum speed range between 2.6 – 3.7 m/s (Dayne et al., 2011). Interestingly, assisted jumping can increase the movement speed, by allowing a faster rate of shortening of the leg extensor musculature and a velocity overload during the jump (Sheppard, Dingley, Janssen, Spratford, Chapman, & Newton, 2011).

     To the best of our knowledge, the research by Hernandez-Preciado et al. (2018) is the only study assessing the acute potentiation effects of the FCM. The CMJ was assessed before and after the performance of a FCM in 31 athletes. The FCM protocol consisted of 3 sets of isometric partial squats, drop jumps, dynamic half-squats and hurdle jumps. CMJ height was measured 5 minutes after each set of the FCM. Hernandez-Preciado et al. (2018) report that, compared to baseline, the vertical jump performance improved by 5.1  1.1% after the first set, by 6.8  1.8% after the second set, and by 8.5  2.9% after the third set. These findings suggest that the FCM can be an effective method to acutely enhance the lower body’s force and power production.

PRACTICAL APLICATIONS:

• The FCM is an effective and time-efficient strategy to improve explosive performance.
• The FCM consists of combining four consecutive exercises: a resistance exercise performed at a near maximal load, a plyometric exercise that mimics the same movement pattern, a resistance exercise trying to maximize the power production, and a plyometric or accelerated plyometric exercise.
• There is no “one size fits all”. The FCM should be applied during specific periods of the season with athletes and with enough training history.
• Work through the entire spectrum of the force-velocity continuum is necessary to improve neuromuscular power.
• Acute potentiation effect of lower body’s force and power production is developed after 3 sets of the FCM.