The non-significant EMG activity changes in the agonist muscles
following antagonist stretching found in the current study supports the idea that antagonist static or dynamic stretching has no effects on agonist muscle
Secondly, the joint moment measured during maximal exercises may have been generated by activity of both agonist and antagonist muscles, possibly leading to an underestimation of the calculated force of the agonist muscles
. Nevertheless, the up to 20% activity of antagonist muscles that can be expected while executing maximal exercises  is smaller than the average 28% variation in the measured joint moments .
The possible reasons for these observations are: (i) positive effect of dynamic stretching on agonist muscles
by allowing a greater number of cross-bridges to form, resulting in an increase in force production, which causes a higher PAP and (ii) an effect of stretching on antagonist muscle by a declining muscle-tendon unit stiffness and formation of a less number of cross-bridges.
Thus, the second possibility that the contractile intensity of agonist muscles
is held in check for some reason when they are employed to accelerate sub-maximal weights must be considered.
We developed a hybrid training system (HTS) that combines electrical stimulation and volitional contractions; it uses the electrically stimulated eccentric antagonist muscle contractions as a resistance to voluntary agonist muscle
In Algorithm 2, most effective point that is capable of maximizing the activity of an agonist muscle
and minimizing the activity of other muscles is calculated before designing a motion path to use in (9) as an initial value.
Resistance equal to that of the patient is an isometric contraction and increases tension in the agonist muscle
but without movement; this is associated with increased strength or tone of this muscle. If the resistance applied is less than that of the patient, the movement will be completed but with greater effort.
Previous studies (3,8,26) have shown a potential effect of PS on agonist muscle
performance due to the possible reduction in antagonist coactivation, storage of elastic energy, and alteration of the triphasic pattern of muscle activation.
The key finding from the current study was the significant increase in agonist muscle
performance during the SR exercise after contract-relax PNF stretching on antagonist muscles (shoulder adductors) compared to the TP.
To date, previous studies have usually included adults, while there are only a few studies in the literature investigating the effects of botulinum toxin injection plus electrical stimulation in patients with CR ([7,14,15]) The aim of the current study was, therefore, to investigate the effectiveness of electrical stimulation applied to the agonist muscles
after the administration of Botulinum toxin A (BTX-A) in children with spastic diplegic CP (SDCP).
During knee extension movements, agonist muscles
generate most of the force whilst antagonist muscles exhibit low-to-moderate force levels [15,35].
Staying in the same position for prolonged periods can result in tightening of the agonist muscles
and weakening of the antagonist muscles; hence posture appears cramped.