Adaptive Force and emotionally related imaginations – preliminary results suggest a reduction of the maximal holding capacity as reaction to disgusting food imagination

Abstract

The link between emotions and motor control has been discussed for years. The measurement of the Adaptive Force (AF) provides the possibility to get insights into the adaptive control of the neuromuscular system in reaction to external forces. It was hypothesized that the holding isometric AF is especially vulnerable to disturbing inputs. Here, the behavior of the AF under the influence of positive (tasty) vs. negative (disgusting) food imaginations was investigated. The AF was examined in n = 12 cases using an objectified manual muscle test of the hip flexors, elbow flexors or pectoralis major muscle, performed by one of two experienced testers while the participants imagined their most tasty or most disgusting food. The reaction force and the limb position were measured by a handheld device. While the slope of force rises and the maximal AF did not differ significantly between tasty and disgusting imaginations (p > 0.05), the maximal isometric AF was significantly lower and the AF at the onset of oscillations was significantly higher under disgusting vs. tasty imaginations (both p = 0.001). A proper length tension control of muscles seems to be a crucial functional parameter of the neuromuscular system which can be impaired instantaneously by emotionally related negative imaginations. This might be a potential approach to evaluate somatic reactions to emotions.

Influence of emotionally affective imaginations on the Adaptive Force in young women: unpleasant imaginations reduce the holding capacity of muscles

“…A priori power analysis (G*Power 3.1.9.7) for group differences (dependent t-test, two-tailed) on the base of the parameter with the lowest effect size of the previous study (unpleasant vs. pleasant imagination; parameter 𝐴𝐹𝑜𝑠𝑐 𝐴𝐹𝑚𝑎𝑥 , dz = 1.390) [11] revealed a necessary sample size of at least n = 9 (α = 0.05, β = 0.95). In the anticipation of possible dropouts and due to an assumed lower effect size because of the improved design with a presumably lower bias, n = 12 participants were measured.…”

“…In first pilot studies the AFisomax was found to be significantly reduced in healthy participants perceiving unpleasant vs. pleasant odors [41] as well as by imagining negative vs. positive food experiences [11]. Both, unpleasant odors and negative food imaginations, are related to the emotion 'disgust'.…”

“…[11,41] Furthermore, during stable adaptation (positive odors/imaginations) the oscillations appeared still under isometric conditions, whereby for unstable adaptation (negative odors/imaginations) they appearedif at allafter the maximal isometric holding capacity was exceeded, thus, during muscle lengthening. [11,41] The primary findings of those exploratory studies led to the assumption, that muscular stability during adaptation to external forces might be impaired by imaginations related to the emotion disgust and possibly also by other negative emotionally affective stimuli. Since the previous study concerning the effect of imaginations on AF had some methodological limitations (no blinding, no randomization, no baseline AF), the aim of the present study was to investigate the influence of positive and negative emotionally affective imaginations on the AF in a revised and improved design including randomization of imagination tasks, single-blinding and baseline measurements.…”

“…[5] The link between emotions and motor control can be explained by the central areas involved in processing bothemotions and motor controle.g., the cerebellum, the basal ganglia and the cingulate cortex. [5][6][7][8][9][10] A related discussion was given in Schaefer et al [11] The topic is also of great interest in medicine. There is a large agreement that mental health issues and complaints of the musculoskeletal system are connected.…”

“…In case of a stable adaptation, the AFisomax is similar or considerably high related to AFmax or to MVIC, respectively. [11,41,42] In case of instability (inadequate adaptation), muscle lengthening starts on a low force level (decreased AFisomax), whereby AFmax reaches a similar high level as for stable adaptations but then during eccentric motion. [11,41] That suggests that the holding capacity has to be clearly differentiated to other force parameters.…”