Movement and stretching imagery during flexibility training

Abstract

The aim of this study was to examine the effect of movement and stretching imagery on increases in flexibility. Thirty volunteers took part in a 4 week flexibility training programme. They were randomly assigned to one of three groups: (1) movement imagery, where participants imagined moving the limb they were stretching; (2) stretching imagery, where participants imagined the physiological processes involved in stretching the muscle; and (3) control, where participants did not engage in mental imagery. Active and passive range of motion around the hip was assessed before and after the programme. Participants provided specific ratings of vividness and comfort throughout the programme. Results showed significant increases in flexibility over time, but no differences between the three groups. A significant relationship was found, however, between improved flexibility and vividness ratings in the movement imagery group. Furthermore, both imagery groups scored significantly higher than the control group on levels of comfort, with the movement imagery group also scoring significantly higher than the stretching imagery group. We conclude that the imagery had stronger psychological than physiological effects, but that there is potential for enhancing physiological effects by maximizing imagery vividness, particularly for movement imagery.     

Movement and stretching imagery during flexibility training

The aim of this study was to examine the effect of movement and stretching imagery on increases in flexibility. Thirty volunteers took part in a 4 week flexibility training programme. They were randomly assigned to one of three groups: (1) movement imagery, where participants imagined moving the limb they were stretching; (2) stretching imagery, where participants imagined the physiological processes involved in stretching the muscle; and (3) control, where participants did not engage in mental imagery. Active and passive range of motion around the hip was assessed before and after the programme. Participants provided specific ratings of vividness and comfort throughout the programme. Results showed significant increases in flexibility over time, but no differences between the three groups. A significant relationship was found, however, between improved flexibility and vividness ratings in the movement imagery group. Furthermore, both imagery groups scored significantly higher than the control group on levels of comfort, with the movement imagery group also scoring significantly higher than the stretching imagery group. We conclude that the imagery had stronger psychological than physiological effects, but that there is potential for enhancing physiological effects by maximizing imagery vividness, particularly for movement imagery.     

The effects of imagery training on fast isometric knee extensor torque development

Abstract

We hypothesized that imagery training would improve the fast onset of neuromuscular activation and thereby fast knee extensor isometric torque development. Forty young healthy participants, not involved in strength training, were assigned to one of four groups: physical training, imagery training, placebo training or control. The three training groups had three 15 min sessions per week for 4 weeks, with a 90° knee angle but were tested also at 120°. At 90° knee angle, maximal torque increased (～8%) similarly in all three training groups. The torque–time integral (contractile impulse) over the first 40 ms after torque onset (TTI40) increased (P < 0.05) after physical training (by ～100%), but only at 90°. This increase was significantly different from the delta values (change pre to post) in the control and placebo groups, whereas delta values in the imagery group were similar to those in the placebo group. The increases in TTI40 following physical training were related (r ² = 0.81, P < 0.05) to significant increases of knee extensor rectified surface EMG at torque onset (EMG40). In conclusion, only physical training led to a knee angle specific increase of contractile impulse that was significantly different from placebo and controls and that was related to improved onset of neuromuscular activation.     

On the role of imagery modalities on motor learning

Abstract

In the present study, we examine specifically how the sensory conditions available during physical practice of a task might influence the subsequent use of motor imagery. First, as a pre-test, participants had to physically reproduce knee joint positions with or without vision. Second, they practised motor imagery (15 and 150 trials) with visual, kinaesthetic or visuo-kinaesthetic imagery. A control group with no imagery was included. Post-tests were then performed 10 min and 24 h after each imagery session in a sensory condition similar to that used in the pre-test. Results showed that efficient motor imagery instructions have to take account of the sensory information available during physical experience of the task: kinaesthetic or visuo-kinaesthetic imagery in a no-vision condition, and visual imagery or, to a lesser extent, visuo-kinaesthetic imagery in a vision condition. Discussion focuses on the role of sensory motor memory on motor prediction to simulate a specific movement, and on the similarities between physical and mental practice in the development of sensory-specific movement representation.     

The effects of imagery training on fast isometric knee extensor torque development

We hypothesized that imagery training would improve the fast onset of neuromuscular activation and thereby fast knee extensor isometric torque development. Forty young healthy participants, not involved in strength training, were assigned to one of four groups: physical training, imagery training, placebo training or control. The three training groups had three 15 min sessions per week for 4 weeks, with a 90 ° knee angle but were tested also at 120 °. At 90 ° knee angle, maximal torque increased (-8%) similarly in all three training groups. The torque-time integral (contractile impulse) over the first 40 ms after torque onset (TTI40) increased (P < 0.05) after physical training (by -100%), but only at 90 °. This increase was significantly different from the delta values (change pre to post) in the control and placebo groups, whereas delta values in the imagery group were similar to those in the placebo group. The increases in TTI40 following physical training were related (r (2) = 0.81, P < 0.05) to significant increases of knee extensor rectified surface EMG at torque onset (EMG40). In conclusion, only physical training led to a knee angle specific increase of contractile impulse that was significantly different from placebo and controls and that was related to improved onset of neuromuscular activation.     

The functional equivalence between movement imagery, observation, and execution influences imagery ability

Based on literature identifying movement imagery, observation, and execution to elicit similar areas of neural activity, research has demonstrated that movement imagery and observation successfully prime movement execution. To investigate whether movement and observation could prime ease of imaging from an external visual-imagery perspective, an internal visual-imagery perspective, and kinesthetic modality, 36 participants (M age = 20.58; SD = 3.11; 18 women and 18 men) completed an adapted version of the Movement Imagery Questionnaire-Revised under four modes of delivery (movement prime, external observation prime, internal observation prime, and image-only). The results revealed that ease of imaging was significantly greater during the movement and observation prime conditions compared to the image-only condition (p < .05). Specifically when priming external visual imagery and internal visual imagery, observation facilitated ease of imaging only when the perspective was congruent with the imagery perspective. The results support the use of movement and observation to facilitate ease of imaging, but highlight the importance of considering the visual perspective when using observation.     

Self-efficacy and imagery use in older adult exercisers

Abstract

The aim of the present study was to investigate the relationship between self-efficacy and imagery use in older male (n = 40) and female (n = 52) exercisers. Participants’ self-efficacy was evaluated using the Self-Efficacy Questionnaire for Exercisers, and their use of imagery was evaluated using the Exercise Imagery Questionnaire. Results revealed that older adult exercisers were most efficacious in terms of the task, followed by scheduling physical activity into their daily routines, and finally overcoming barriers related to physical activity. Older adult exercisers also reported using appearance and technique imagery to much the same extent, but used both significantly more than energy imagery. In addition, energy imagery predicted task self-efficacy but none of the three functions of imagery predicted barrier and scheduling self-efficacy.     

Comparing self-report and mental chronometry measures of motor imagery ability

Abstract

The present study investigated the relationship between two of the most common measures of motor imagery ability, self-report ratings, and chronometric assessment. This was done for three types of imagery modalities: external visual imagery (EVI), internal visual imagery (IVI), and kinesthetic imagery (KI). Measures of imagery ability (i.e. self-report and mental chronometry) were also compared across skill levels. Participants (N?=?198) completed the Movement Imagery Questionnaire-3 (MIQ-3) to generate self-report ratings. Chronometric assessment was obtained by recording the duration of each MIQ-3 movement imaged and physically performed and then calculating a discrepancy score. There were no significant correlations between self-report and mental chronometry for any of the three motor imagery types (p?>?.05). When assessing the different types of motor imagery ability using self-report ratings, elite athletes had significantly higher KI than IVI, which was in turn significantly higher than EVI (p?<?.05). When assessing motor imagery ability using mental chronometry, there were no significant differences in imagery type (p?>?.05). Findings suggest both measures address different components of MI quality and should be used together to obtain a more comprehensive assessment of motor imagery ability.     

Impact forces and neck muscle activity in heading by collegiate female soccer players

Three soccer header types (shooting, clearing and passing) and two heading approaches (standing and jumping) were manipulated to quantify impact forces and neck muscle activity in elite female soccer players. The 15 participants were Division I intercollegiate soccer players. Impact forces were measured by a 15-sensor pressure array secured on the forehead. The electromyographic (EMG) activity of the left and right sternocleidomastoid and trapezius muscles was recorded using surface electrodes. Maximum impact forces and impulses as well as the EMG data were analysed with separate repeated-measures analyses of variance. Impact forces and impulses did not differ among the header types or approaches. Higher values were found for jumping versus standing headers in the mean normalized EMG for the right sternocleidomastoid. In addition, the integrated EMG was greater for the right sternocleidomastoid and right and left trapezius (P < 0.05). The sternocleidomastoid became active earlier than the trapezius and showed greater activity before ball contact. The trapezius became active just before ball contact and showed greater activity after ball contact. The increased muscle activity observed in the neck during the jumping approach appears to stabilize the connection between the head and body, thereby increasing the stability of the head-neck complex.     

Impact forces and neck muscle activity in heading by collegiate female soccer players

Three soccer header types (shooting, clearing and passing) and two heading approaches (standing and jumping) were manipulated to quantify impact forces and neck muscle activity in elite female soccer players. The 15 participants were Division I intercollegiate soccer players. Impact forces were measured by a 15-sensor pressure array secured on the forehead. The electromyographic (EMG) activity of the left and right sternocleidomastoid and trapezius muscles was recorded using surface electrodes. Maximum impact forces and impulses as well as the EMG data were analysed with separate repeated-measures analyses of variance. Impact forces and impulses did not differ among the header types or approaches. Higher values were found for jumping versus standing headers in the mean normalized EMG for the right sternocleidomastoid. In addition, the integrated EMG was greater for the right sternocleidomastoid and right and left trapezius (P < 0.05). The sternocleidomastoid became active earlier than the trapezius and showed greater activity before ball contact. The trapezius became active just before ball contact and showed greater activity after ball contact. The increased muscle activity observed in the neck during the jumping approach appears to stabilize the connection between the head and body, thereby increasing the stability of the head-neck complex.     

Is high soleus muscle activity during the stance phase of the running cycle a potential risk factor for the development of medial tibial stress syndrome? A prospective study

ABSTRACT

To assess the impact of lower-leg muscle activity during the stance phase of running on the development of medial tibial stress syndrome (MTSS), in 123 healthy participants (18.2 ± 0.8 years), dynamic and static foot posture, and soleus and tibialis anterior muscle activity during the stance phase of running were measured before a 17-week track- and field-course. After the course, MTSS was identified in 20.5% of the participants. MTSS participants had a higher body mass (ES = 1.13), body mass index (BMI) (ES = 1.31), lower previous vigorous physical activity level (ES = 0.84) and VO_2max (ES = 0.61), greater dynamic foot pronation (ES = 0.66), higher soleus peak EMG amplitude during the absorption (ES = 0.60) and propulsion phases (ES = 0.56) of running, and a history of MTSS (OR = 6.38) (p < 0.05). Stepwise logistic regression showed BMI, dynamic foot index, soleus peak EMG amplitude during propulsion, MTSS history and previous vigorous physical activity were predictors of MTSS. The model predicted 96.6% of the healthy participants and 56.5% of the MTSS participants and correctly classified 88.4% of overall cases. Coaches and sports-medicine professionals that screen for injury risk should consider adopting a comprehensive evaluation that includes these parameters.     

Quadriceps EMG muscle activation during accurate soccer instep kicking

Six competitive soccer players were recruited to examine EMG activation in three quadriceps muscles during a kicking accuracy task. Participants performed three maximum instep place kicks of a stationary ball, 11 m perpendicular from the centre of the goal line towards targets (0.75 m(2)) in the four corners of the goal. Surface EMG of the vastus lateralis, vastus medialis, and rectus femoris of the kicking leg was normalized and averaged across all participants to compare between muscles, targets, and the phase of the kick. Although no significant difference were observed between muscles or kick phases, kicks to the right targets produced significantly greater muscle activity than those towards the left targets (P < 0.01). In addition, kicks towards the top right target demonstrated significantly greater muscle activity than towards the top and bottom left (P < 0.01). Under accurate soccer shooting conditions, kicks aimed to the top right corner of the goal demonstrated a higher level of quadriceps muscle activation than those towards the other corners.     

Sport imagery ability predicts trait confidence,and challenge and threat appraisal tendencies

Abstract

The present study investigated the interplay among athletes' sport imagery ability, trait confidence, and tendency to appraise situations as a challenge and threat. The potential mediating role of trait confidence was also tested. A total of 207 athletes (M _age =19.44; s=1.26; 90 female, 117 male) completed the Sport Imagery Ability Questionnaire to assess ease of imaging skill, strategy, goal, affect and mastery imagery, the confidence subscale of the Competitive Trait Anxiety Inventory to measure trait confidence, and the Cognitive Appraisal Scale to assess tendencies to appraise sport situations as a challenge and as a threat. Structural equation modelling supported a model wherein mastery and goal imagery ability both positively predicted confidence, which in sequence positively predicted challenge appraisal and negatively predicted threat appraisal tendency. Partial support was found for confidence mediating the relationship between mastery imagery ability and appraisal tendencies. In addition, ease of imaging mastery and affect imagery directly predicted challenge appraisal tendency (positive direction), and ease of imaging mastery imagery directly predicted threat appraisal tendency (negative direction). Results highlight the importance of motivational imagery ability and the need to assess athletes' ability to image different content.     

The relationship between the use of kinaesthetic imagery and different visual imagery perspectives

In two studies, we examined the strength of relationship between internal and external visual imagery with kinaesthetic imagery. In Study 1, 56 participants completed the Vividness of Movement Imagery Questionnaire and the Movement Imagery Questionnaire. Pearson's product-moment correlations failed to reveal a significant correlation between external visual imagery and kinaesthetic imagery. However, the correlation between internal visual imagery and kinaesthetic imagery approached significance. In Study 2, the instructional set of the Vividness of Movement Imagery Questionnaire was changed to make the participant the 'agent' of the external visual perspective images rather than somebody else. Sixty-four participants completed the two questionnaires. The results indicated a significant correlation between external visual imagery and kinaesthetic imagery (r = 0.60, P < 0.01). However, the correlation between internal visual imagery and kinaesthetic imagery was non-significant (r = 0.23, P > 0.01). The results are discussed in relation to who is the agent of the image and the processes that may underlie kinaesthetic imagery. The implications for researchers trying to establish the functional, behavioural and neurological differences within, and across, imagery modalities are considered.     

Improving the TAMI for use with athletes

Abstract

Athletes have been shown to have greater movement imagery abilities than non-athletes. However, since these differences were observed using questionnaires where participants subjectively judged the vividness of performing imagined movements, it is possible that responses could be biased by other factors such as social desirability. One possible solution is to use an objective test, such as the Test of Ability in Movement Imagery (TAMI; Madan, C. R., & Singhal, A. (2013). Introducing TAMI: An objective test of ability in movement imagery. Journal of Motor Behavior, 45, 153–166.). Unfortunately, young adults perform relatively well on the TAMI, leaving little room for statistical sensitivity in observing higher scores. Here we propose an alternate scoring method for the TAMI that resolves this limitation by weighing items according to their difficulty. We apply this scoring method to existing data and show that this improves the TAMI’s selectivity to measuring ability in movement imagery, rather than related imagery processes. Thus, we have successfully improved the TAMI to be more suited for use with athletic populations.     

The relationship between the use of kinaesthetic imagery and different visual imagery perspectives

In two studies, we examined the strength of relationship between internal and external visual imagery with kinaesthetic imagery. In Study 1, 56 participants completed the Vividness of Movement Imagery Questionnaire and the Movement Imagery Questionnaire. Pearson's product–moment correlations failed to reveal a significant correlation between external visual imagery and kinaesthetic imagery. However, the correlation between internal visual imagery and kinaesthetic imagery approached significance. In Study 2, the instructional set of the Vividness of Movement Imagery Questionnaire was changed to make the participant the ‘agent’ of the external visual perspective images rather than somebody else. Sixty-four participants completed the two questionnaires. The results indicated a significant correlation between external visual imagery and kinaesthetic imagery (r?=?0.60, P?<0.01). However, the correlation between internal visual imagery and kinaesthetic imagery was non-significant (r?=?0.23, P?>0.01). The results are discussed in relation to who is the agent of the image and the processes that may underlie kinaesthetic imagery. The implications for researchers trying to establish the functional, behavioural and neurological differences within, and across, imagery modalities are considered.     

Comparison of EMG activity during stable and unstable push-up protocols

Abstract

This experiment examined muscle activation measured using electromyography (EMG) during a standardized push-up performed on stable and unstable surfaces. Fifteen highly trained participants performed four push-ups: standard (hands and feet on the floor), either the hands or feet on an unstable surface (single instability), and with both hands and feet on unstable surfaces (dual instability). Unstable surfaces were created using a stability ball and an extreme balance board. EMG activity was recorded from three core stabilizers (erector spinae, rectus abdominus and internal obliques), one prime mover (triceps), and one lower body stabilizer (soleus). The EMG time series were smoothed using a 10-point moving average and root mean squares (RMS) were calculated for the entire time series. The results showed that push-ups performed with dual instability had significantly greater EMG activation compared to single instability or the stable push-up. In addition, as instability increased, there was a greater amount of muscle activation for the core stabilizers, prime movers and lower body stabilizers. The findings are consistent with the position that unstable surfaces in conjunction with standard exercises can be used to increase activation of core trunk stabilizers. This may in turn provide increased trunk strength and greater resistance to injury.     

Measurement of motivational imagery abilities in sport

Athletes report using imagery most often to successfully cope with and master challenging situations. This function of imagery is termed "motivational general-mastery" and includes imagining being focused, confident and in control in difficult circumstances. Also, athletes often use imagery to regulate their arousal levels (e.g. relaxing, psyching up) and this function of imagery is termed "motivational-general arousal". While most athletes report employing these two motivational functions of imagery, their ability to do so has not been examined. The aim of the present study was to develop a measure of motivational general sport imagery ability, the Motivational Imagery Ability Measure for Sport (MIAMS). This was accomplished through three phases. Across these phases, evidence was generated showing that the psychometric properties of the instrument are adequate. In addition, the relationship of scores on the MIAMS to demographic variables, including sex, sport type and competitive standard, were examined. It was found that athletes participating at a competitive level scored higher on the MIAMS than athletes participating at a recreational level.     

Neural mechanisms of strength increase after one-week motor imagery training

The neural mechanisms explaining strength increase following mental training by motor imagery (MI) are not clearly understood. While gains are mostly attributed to cortical reorganization, the sub-cortical adaptations have never been investigated. The present study investigated the effects of MI training on muscle force capacity and the related spinal and supraspinal mechanisms. Eighteen young healthy participants (mean age: 22.5?±?2.6) took part in the experiment. They were distributed into two groups: a control group (n?=?9) and an MI training group (n?=?9). The MI group performed seven consecutive sessions (one per day) of imagined maximal isometric plantar flexion (4 blocks of 25 trials per session). The control group did not engage in any physical or mental training. Both groups were tested for the isometric maximal plantar flexion torque (MVC) and the rate of torque development (RTD) before and after the training session. In addition, soleus and medial gastrocnemius spinal and supraspinal adaptations were assessed through the recording of H-reflexes and V-waves, with electrical stimulations of the posterior tibial nerve evoked at rest and during MVC, respectively. After one week, only the MI training group increased both plantar flexion MVC and RTD. The enhancement of muscle torque capacity was accompanied by significant increase of electromyographic activity and V-wave during MVC and of H-reflex at rest. The increased cortical descending neural drive and the excitability of spinal networks at rest could explain the greater RTD and MVC after one week of MI training.