The effect of a psyching strategy on neuromuscular activation and force production in strength-trained men

IMMEDIATE EFFECT OF MENTAL SIMULATION ON SELF-CONFIDENCE AND PERFORMANCE WHEN PERFORMING STANDING SALTO BACKWARDS IN GYMNASTS

The aim of this study was to examine the combined effect of mental imagery as well as visualization on performance, self-confidence, and self-report during the performance of the standing salto backward. Eighteen gymnasts (age 22.11 ± 1.71 years) voluntarily participated in this study. Once the warm-up was completed, subjects performed a standing salto backward tucked on the force-plate to determine the baseline performance before each experimental session. Subsequently, subjects were given specific intervention instructions and were asked to perform the standing salto backward tucked to the best of their ability. Participants were asked to engage in two mental strategies namely mental imagery and visualization for 1 min just before performing (Standing salto backward tucked). The results of the present study show that the combined mental simulation (MI and V), generate a potential improvement in performance during the execution of the standing salto backward as well as self-confidence and self-evaluation.

Just noticeable differences for elbow joint torque feedback

Joint torque feedback is a new and promising means of kinesthetic feedback imposed by a wearable device. The torque feedback provides the wearer temporal and spatial information during a motion task. Nevertheless, little research has been conducted on quantifying the psychophysical parameters of how well humans can perceive external torques under various joint conditions. This study aims to investigate the just noticeable difference (JND) perceptual ability of the elbow joint to joint torques. The paper focuses on the ability of two primary joint proprioceptors, the Golgi-tendon organ (GTO) and muscle spindle (MS), to detect elbow torques, since touch and pressure sensors were masked. We studied 14 subjects while the arm was isometrically contracted (static condition) and was moving at a constant speed (dynamic condition). In total there were 10 joint conditions investigated, which varied the direction of the arm's movement and the preload direction as well as torque direction. The JND torques under static conditions ranged from 0.097 Nm with no preload to 0.197 Nm with a preload of 1.28 Nm. The maximum dynamic JND torques were 0.799 Nm and 0.428 Nm, when the arm was flexing and extending at 213 degrees per second, respectively.

Shouting strengthens maximal voluntary force and is associated with augmented pupillary dilation

Previous research has demonstrated that human maximal voluntary force is generally limited by neural inhibition. Producing a shout during maximal exertion effort enhances the force levels of maximal voluntary contraction. However, the mechanisms underlying this enhancement effect on force production remain unclear. We investigated the influence of producing a shout on the pupil-linked neuromodulatory system state by examining pupil size. We also examined its effects on the motor system state by examining motor evoked potentials in response to transcranial magnetic stimulation applied over the contralateral primary motor cortex, and by evaluating handgrip maximal voluntary force. Analysis revealed that producing a shout significantly increased handgrip maximal voluntary force, followed by an increase in pupil size and a reduction of the cortical silent period. Our results indicate that producing a shout increased handgrip maximal voluntary force through the enhancement of motor cortical excitability, possibly via the enhancement of noradrenergic system activity. This study provides evidence that the muscular force-enhancing effect of shouting during maximal force exertion is related to both the motor system state and the pupil-linked neuromodulatory system state.

The Competition-Day Preparation Strategies of Strongman Athletes

Winwood, PW, Pritchard, HJ, Wilson, D, Dudson, M, and Keogh, JWL. The competition-day preparation strategies of strongman athletes. J Strength Cond Res 33(9): 2308-2320, 2019-This study provides the first empirical evidence of the competition-day preparation strategies used by strongman athletes. Strongman athletes (n = 132) (mean ± SD: 33.7 ± 8.1 years, 178.2 ± 11.1 cm, 107.0 ± 28.6 kg, 12.8 ± 8.0 years general resistance training, 5.9 ± 4.8 years strongman implement training) completed a self-reported 4-page internet survey on their usual competition-day preparation strategies. Analysis of the overall group and by sex, age, body mass, and competitive standard was conducted. Ninety-four percent of strongman athletes used warm-ups in competition, which were generally self-directed. The typical warm-up length was 16.0 ± 8.9 minutes, and 8.5 ± 4.3 minutes was the perceived optimal rest time before the start of an event. The main reasons for warming up were injury prevention, to increase activation, and increase blood flow/circulation, temperature, and heart rate. Athletes generally stated that competition warm-ups were practiced in training. Dynamic stretching, foam rolling, and myofascial release work were performed during warm-ups. Warm-up intensity was monitored using the rate of perceived exertion, perceived speed of movement, and training load (as a percentage of 1 repetition maximum). Cognitive strategies were used to improve competition performance, and psychological arousal levels needed to increase or be maintained in competition. Electrolyte drinks, caffeine, and preworkout supplements were the commonly used supplements. These data will provide strongman athletes and coaches some insight into common competition-day preparation strategies, which may enhance competition performances. Future research could compare different competition-day preparation strategies in an attempt to further improve strongman competition performance and injury prevention.

CORP: Measurement of upper and lower limb muscle strength and voluntary activation

Muscle strength, the maximal force-generating capacity of a muscle or group of muscles, is regularly assessed in physiological experiments and clinical trials. An understanding of the expected variation in strength and the factors that contribute to this variation is important when designing experiments, describing methodologies, interpreting results, and attempting to replicate methods of others and reproduce their findings. In this review (Cores of Reproducibility in Physiology), we report on the intra- and inter-rater reliability of tests of upper and lower limb muscle strength and voluntary activation in humans. Isometric, isokinetic, and isoinertial strength exhibit good intra-rater reliability in most samples (correlation coefficients ≥0.90). However, some tests of isoinertial strength exhibit systematic bias that is not resolved by familiarization. With the exception of grip strength, few attempts have been made to examine inter-rater reliability of tests of muscle strength. The acute factors most likely to affect muscle strength and serve as a source of its variation from trial-to-trial or day-to-day include attentional focus, breathing technique, remote muscle contractions, rest periods, temperature (core, muscle), time of day, visual feedback, body and limb posture, body stabilization, acute caffeine consumption, dehydration, pain, fatigue from preceding exercise, and static stretching >60 s. Voluntary activation, the nervous system’s ability to drive a muscle to create its maximal force, exhibits good intra-rater reliability when examined with twitch interpolation (correlation coefficients >0.80). However, inter-rater reliability has not been formally examined. The methodological factors most likely to influence voluntary activation are myograph compliance and sensitivity; stimulation location, intensity, and inadvertent stimulation of antagonists; joint angle (muscle length); and the resting twitch.

Comparison between the Ki-hap technique and verbal encouragement on activation of abdominal muscles in healthy participants

The aim of this study was to investigate the comparison between a Ki-hap, defined as a psyching-up technique, and verbal encouragement, defined as a verbal command by a third party, on abdominal muscle activation during performance of the crunch exercise in healthy participants. Ninety participants were randomly allocated to the following three groups: crunch only exercise group (CG, n₁ = 30), crunch exercise with Ki-hap group (CKG, n₂ = 30), and crunch exercise with Ki-hap and verbal encouragement group (CKVG, n₃ = 30). The interventions were conducted over three trials with each group, and measurements involving each participant, were performed by a single examiner. The activation of the rectus abdominis (RA), external oblique (EO), and internal oblique (IO) muscles were evaluated using electromyography (EMG) during performance of the crunch exercise by the CG, CKG, and CKVG. Our results showed a significantly greater increase in the EMG patterns of all muscles during performance of the crunch exercise in the CKG (p < 0.05) compared to those in the CG and CKVG. The results also showed that there was a significantly greater increase in the activation of the EO and IO muscles in the CKVG (p < 0.05) compared with that in the CG. These findings demonstrated that the addition of the Ki-hap technique and verbal encouragement, during performance of the crunch exercise, improves activation of the abdominal muscles.

Time interval moderates the relationship between psyching-up and actual sprint performance

This study attempted to test whether the strongest effect of psyching-up (PU) strategy on actual sprint performance can be observed when the strategy is used immediately (or almost) before performance compared with when there is a delay between PU and performance. To do so, 16 male sprinters (age, 20.6 ± 1.3 years; body mass, 77.5 ± 7.1 kg; height, 180.8 ± 5.6 cm) were enrolled in a counterbalanced experimental design in which participants were randomly assigned to 10 sessions (2 [Experimental Condition: imagery vs. distraction] × 5 [Time Intervals: no interval, 1 minute, 2 minutes, 3 minutes, and 5 minutes]). Before performing the experimental tasks, participants rated: (a) the Hooper index, (b) their degree of self-confidence, and (c) after the completion of the experimental test; they rated their perceived effort. Findings showed that the imagery significantly improved sprint performance. Specifically, the imagery enhanced performance on the phase of acceleration (0-10 m) and on the overall sprint (0-30 m) when used immediately before performance and at 1- and 2-minute intervals but not for 3- and 5-minute intervals. These findings support the hypothesis that the potential effect of the PU strategy on performance vanishes over time. The pre-experimental task Hooper and self-efficacy indexes did not change across the 10 experimental sessions, reinforcing the view that the observed performance changes were directly caused by the experimental manipulation and not through any altered status of the athletes (self-efficacy, fatigue/recovery, and stress). The potential mechanisms underlying such a process and practical applications are discussed.

[Measuring the handgrip strength of geriatric patients]

The handgrip strength of geriatric patients can be measured when the patient is hospitalized. This article elaborates on the intrinsic and extrinsic factors which have a direct or indirect influence on handgrip strength. For the best results the tests need to be taken in the best circumstances with attention to individual differences and the age of the patient. Handgrip strength as determination of biological vitality is a key concept. Besides the physical characteristics there are many psychological factors (cognition, psyching-up, test attitude…) influencing the results. These are barely mentioned or not mentioned at all in the usual procedures. Research of handgrip strength testing theories is mostly focused on young, healthy adults and less on elderly patients. The main goal of this article is stimulating experimental research on the measurement of handgrip strength with elderly people and involving them more actively with the procedure. It is not enough to acquire insight in function and predicting characteristics of handgrip strength. Next to the aiming for the best test performance is 'working interactively with elderly patients' a goal on itself in the modern vision of health care.

Effects of instructional and motivational self-talk on the vertical jump

The purpose of this study was to investigate the effects of instructional and motivational self-talk on performance and the kinematics of the vertical jump. After completing a 10-minute warm-up on a stationary bike, 12 men (mean +/- SD; 20.8+/- 3.0 years, 77.8 +/- 13.5 kg, 1.78 +/- 0.07 m) and 12 women (22.1 +/- 5.8 years, 62.6 +/- 6.7 kg, 1.65 +/- 0.05 m) performed 4 vertical jumps, 3 minutes apart, on a force plate set at a 1000-Hz sampling frequency. Before each trial, participants engaged in 1 of 4 counterbalanced interventions, verbalized out loud, which included motivational self-talk, instructional self-talk, neutral self-talk, or no instruction. One-way analysis of variance with repeated measures, followed by paired t-tests with a Bonferroni adjustment, were used to analyze data. Both instructional (0.415 m) and motivational (0.414 m) self-talk led to greater center-of-mass displacement than neutral self-talk (0.403 m, p = 0.001 and 0.003, respectively, alpha set at 0.008). Both instructional (263.9 N x s) and motivational self-talk (261.2 N x s) led to greater impulse than neutral self-talk (254.1 N x s, p = 0.005 and 0.004, respectively, alpha set at 0.025). Both instructional self-talk (582.6 degrees x s-1) and motivational self-talk (592.3 degrees x s-1) led to quicker angular rotation about the knee than neutral self-talk (565.8 degrees x s-1, p = 0.001 and 0.018, respectively, alpha set at 0.025). These results may indicate that self-talk leads to greater angular velocity about the knee, thus generating greater impulse and increased jump height-a conjecture that needs empirical testing. Self-talk may contribute to improved performance in sports requiring power-based skills.

The role of self-talk in the awareness of physiological state and physical performance

Different studies have suggested that the majority of self-talk during exercise is either positive or neutral in character. The majority of 'thoughts' during low-intensity exercise have been described as being dissociative conversational chatter. However, with increasing exercise intensity, there is a greater percentage of associative and motivational thoughts, which includes thoughts about feeling and affect, body monitoring, command, instruction and pace monitoring. It has been suggested that self-talk is necessary for creating a time 'wedge' between the activity described by the self-talk, and the self-talk itself. The information redundancy created by this time-wedge allows the capacity for reflection about what is occurring, and self-awareness of the part played by the individual themselves in the activity being performed. Self-talk may be a discussion between a singular 'I' and a singular 'me', or may be a multi-party dialogue. There are anatomical correlates to self-talk, with neural activity in a number of brain areas related to the occurrence of both overt and subvocal self-talk, particularly in Broca's region in the left frontal cortex, and Wernicke's region in the left posterior superior temporal cortex. Whether specific training of self-talk can improve performance is controversial, although recent studies have suggested that task-specific self-talk appears to have a beneficial effect on physical performance. Further studies are required to assess the ability of physical or mental training to modify self-talk in a beneficial and permanent manner, and whether these changes affect an individual's exercise performance and sense of self.

Maximal strength and cortisol responses to psyching-up during the squat exercise

We studied the effect of psyching-up on one-repetition maximum (1-RM) performance and salivary cortisol responses during the squat exercise. Ten men (age 21.6+/-1.4 years; mean+/-s) and ten women (age 22.4+/-2.8 years) with weight training experience of 4.5+/-2.0 years participated in this study. One-repetition maximum squats were performed on a Smith machine during each of two different intervention conditions that were counterbalanced and consisted of a free choice psych-up and a cognitive distraction. Saliva samples were obtained at the beginning of each test session and immediately after the final 1-RM attempt. No significant difference in 1-RM was identified between psyching-up (104+/-50 kg) and cognitive distraction (106+/-52 kg). Performing a 1-RM in the squat exercise significantly increased salivary cortisol concentrations during both conditions (P<0.05). There was no significant difference in salivary cortisol responses between conditions. These results suggest that psyching-up does not increase 1-RM performance during the squat exercise in strength-trained individuals.

'Psyching-up' and muscular force production

Psyching-up refers to self-directed cognitive strategies used immediately prior to or during skill execution that are designed to enhance performance. This review focuses on research that has investigated the effect of psyching-up on force production; specifically, strength, muscular endurance and power. Although firm conclusions are not possible, the research tentatively suggests that psyching-up may enhance performance during dynamic tasks requiring strength and/or muscular endurance. However, more research is required. Power has received scant empirical attention and there are not enough data to support any conclusions. Preparatory arousal appears to be the most effective strategy although other strategies like imagery, self-talk and attentional focus also have empirical support. The range of tasks that have been used to measure force production have been limited to movements such as handgrip, leg extension, bench press, sit-ups, press-ups, pull-ups, and the standing broad jump. Additionally, most studies have used undergraduate and/or untrained samples. Only a very small number of studies have examined well-trained individuals. Currently, no explanation for why psyching-up may influence force production has any substantive support. Although a small number of studies have examined moderating and mediating variables, few consistent patterns have emerged and knowledge in this area is somewhat restricted. Given the importance that many athletes place on their mental preparation just prior to performance this is an area that warrants further examination. Research needs to examine a range of complex sport-specific tasks and use well-trained samples. Additionally, research needs to further examine why psyching-up may enhance force production.