American Football:

Longitudinal Changes in the Strength and Power

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American football is a team invasion sport that requires your players to have higher levels of strength, muscular power, speed, agility, and anaerobic conditioning.

The physical performance of these players is very much required during training and matches.

According to Trexler et al (2017) in this sport, there is a combination of size, strength, speed and power that respects the tactical particularities played by each function.

It seems that both linemen (centers, guards, tackles, defensive tackles, defensive ends, linebackers, and tight ends) as well as backs players (running backs, quarterbacks, wide receivers, and defensive backs) would benefit from a specific strength and power training program.

The constant collisions that occur in a match, both defense and attack use the maximum strength as well as the power of the players.

In an overview conducted by McGuigan et al (2013), the researchers argue that strength training is important for all sports modalities, aiming for improvements in athletic performance and injury prevention.

However, they point out that many times the strength levels acquired by athletes are not well transferred to functional motor action.

For example, strength gains do not necessarily imply improvements in agility which is a motor capacity dependent on specific visual, auditory and kinesthetic stimuli (McGuigan et al, 2013).

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Smith et al. (2014) studied three different forms of strength training in NCAA football players: hypertrophy (body mass gain), maximal strength, and power for 10-weeks.

The hypertrophy group improved on the 1RM bench press, 1RM squat, and power clean.

The maximum strength group also improved 1RM bench press, 1RM squat and power clean significantly.

Finally, the power group, significantly improved only the power clean exercise.

When we refer to muscle strength, we should not forget the muscular quality presented by the athletes.

One research was concerned with analyzing the muscle quality of NCAA football players.

Melvin et al. (2014) evaluated the muscle quality of NCAA football players through analysis of the muscle cross sectional area (mCSA) and echo intensity of the vastus lateralis.

The following mCSA values were found:

Quarterbacks (38.4±6.9 cm²);

  • Running Backs (41.3±1.7 cm²);
  • Tight Ends (36.6±5.4 cm²);
  • Linebackers (37.5±5.3* cm²);
  • Defensive Backs (37.3±5.4* cm²);
  • Kickers/Punters (34.2±6.0* cm²);
  • Defensive Lineman (46.7±4.2 cm²);
  • Offensive Lineman (42.0±5.5 cm²);
  • Wide Receivers (32.3±5.7* cm²);

The differences found in the mCSA values are related to the different tactical tasks of the athletes.

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Thinking scientifically, it would be interesting to find out the behavior of these two variables (upper and lower limb strength and power of the lower limb) longitudinally.

Reviewing the literature on American football, I have noted some longitudinal studies that address anthropometric issues and physical performance of these athletes (Anzell et al, 2013 ; Hoffman et al, 2011 ; Jacobson et al, 2013 ; Trexler et al, 2017 ; Stodden & Galitski, 2010).

In the view of Stodden & Galitski (2010) longitudinal studies are relevant to analyze neuromuscular adaptations of athletes over time.

The idea that athletes will progress their adaptations in a linear curve has been widespread.

However, this line of reasoning does not always prevail when we look closely at the results of longitudinal research.

Perhaps, progressive linear adaptations are more present in the early stages of these athletes’ sports career.

The so-called functional adaptation window is what would allow this “phenomenon” to occur (Stodden & Galitski, 2010).

The infographic was adapted from Hoffman et al (2011). Performance changes during a college playing career in NCAA Division III football athletes. Journal of Strength and Conditioning Research, 25 (09); 2351–2357.


  • ***This text was originally written in my BLOG***


Anzell et al (2013). Changes in height, body weight, and body composition in American football players from 1942 to 2011. Journal of Strength and Conditioning Research, 27 (02); 277–284.

Hoffman et al (2011). Performance changes during a college playing career in NCAA Division III football athletes. Journal of Strength and Conditioning Research, 25 (09); 2351–2357.

Jacobson et al (2013). Longitudinal morphological and performance profiles for American, NCAA Division I football players. Journal Strength and Conditioning Research, 27 (09); 2347–2354.

McGuigan et al (2013). Strength training for athletes: does it really help sports performance? International Journal of Sports Physiology and Performance, 07 (01); 02–05.

Melvin et al (2014). Muscle characteristics and body composition of NCAA division I football players. Journal of Strength and Conditioning Research, 28 (12); 3320–3329.

Smith et al (2014). The effects of resistance training priorization in NCAA Division I football summer training. Journal Strength and Conditioning Research, 28 (01); 14–22.

Stodden & Galitski (2010). Longitudinal effects of a collegiate strength and conditioning program in American football. Journal of Strength and Conditioning Research, 24 (09); 2300–2308.

Trexler et al (2017). Longitudinal body composition changes in NCAA Division I College football players. The Journal of Strength and Conditioning Research, 31 (01); 01–08.

Vretaros, A (2016). Conditioning for American Football. Available in:

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