Sport-specific strength training
Sport-specific strength training - better than "ordinary" strength training?
You often hear that sport-specific strength training is crucial for improving performance in sport. But what exactly is sport-specific strength training? Let's get to the bottom of it.
Neuromuscular adaptations to strength training
If strength training is done correctly, it leads to an increase in mechanical power (force times speed). This newly gained "strength" is due to neuromuscular adaptations. In other words, the body undergoes neural and/or muscular adaptations.
Neural adaptations are movement-specific and can only be transferred to a limited extent between individual exercises. For this reason alone, it makes little sense to understand sport-specific strength training as an imitation of sport-specific movements. These adaptations take place spinally (in the spinal cord) and supraspinally (in the brain). More strength therefore arises, on the one hand, from the neuromuscular system activating the muscles with more "drive", and on the other hand from an increase in muscle fibre cross-sections.
The strength gained in the first few days is due to the following neural adaptations:
Reduction of co-activation of agonists and antagonists (Carolan and Cafarelli 1992)
Increase in the firing rate of motor units (Duchateau 2006)
During maximal voluntary force exertion, recruitment is normally maximal. An increase in recruitment (during maximal contractions) and a synchronisation of the action potentials of the involved motor neurons are, unlike increased firing frequency and reduced co-activation, not a cause of the neurally driven increase in strength. Strength training therefore does not lead to more synchronised release of action potentials between motor units during muscle contractions. The increase in synchronicity is rather a consequence of the decrease in movement complexity (grasping vs. playing the piano).
Intermuscular coordination - the key to success!
"Intermuscular coordination", understood as the temporal coding of the force (or torque) application of the involved muscles (with regard to timing and force level), is certainly to a large extent decisive for movement speed. Notably, this involves both the activation and the inhibition of muscles.
While it is likely that with appropriate training the RFD (rate of force development, or increase in force per unit of time) can be increased on the machine, it remains completely open what physiological significance this may have for everyday movements. This has to do with the function-dependent recruitment of motor units.
Intermuscular coordination should be trained within the sport with sport-specific movements (technique!).
The force curve - sport-specific strength training for long muscles.
The active force that a fibre can generate as a linear motor at constant length (isometric) depends on its current length. In the lengthened state the force is smaller, because the overlap of actin and myosin is smaller and thus the maximum number of bonds is reduced. In the shortened state an inhibition occurs, because the overlap with neighbouring sarcomeres reduces bridge activity.
To be fast at the muscle level, long muscle fibres (many sarcomeres in series) are certainly beneficial. Each sarcomere can shorten at the same maximum speed. If more sarcomeres are connected in series, the fibre can shorten over a greater distance in the same unit of time, and this results in a higher speed.
Speed-force relationship
Muscle force decreases as shortening speed increases. The higher the concentric shortening speed, the smaller the muscle force. Force increases the slower the movement speed is, or the greater the external resistance is, the less quickly it can be moved.
In eccentric contraction, the muscle has more force than in concentric or isometric contraction.
If the goal is to build muscle strength, the movement speed should be slow, because then the internal force is greater!
So what does sport-specific strength training look like?
Sporting activities stress different parts of the body to different degrees, so that a often one-sided, sport-specific adaptation of the musculature occurs. Ultimately, muscular imbalances (in the muscle chain, between antagonists, within the muscle itself) can result. Badminton players who are right-handed, for example, have more pronounced musculature on the right side of the body compared with the left side (forearm, shoulder, back and leg muscles).
Therefore, the following points should be observed for sport-specific strength training:
The "performance musculature" should be trained on both sides (left and right half of the body).
In addition to the "performance musculature", its antagonists must also be strengthened (agonist - antagonist).
Muscles that are important in the sporting activity but not necessarily developed by it must also be trained (e.g. stabilising musculature).
Training should include the whole body and not just individual parts of the body.
Individual wishes and health limitations of the athlete must be taken into account.
Strength training should be seen as a supplement to the actual sport and helps to compensate for sport-specific muscular deficits.
It is also important to coordinate strength training with the practice of the sport in terms of timing so that no mutual negative effects arise. For example, any strength training should be started when the body is recovered. It makes no sense to do strength training after an intense training session in the relevant sport. Conversely, it also makes no sense to follow intensive strength training with, for example, coordination exercises.
Sport-specific strength training ≠ "sport-specific" exercise execution! Sport-specific training programmes differ from conventional ones only in that the choice and order of exercises place emphasis that corresponds to the sport.
