Volume 8, Issue 1 -

The present study sought to describe the various reasons why athletes choose to manipulate the speeds of their images (i.e. image in slow motion, real-time, or fast motion). Athletes ( N = 9) were interviewed using a one-on-one, semi-structured interview format. All interviews were transcribed verbatim and content analyzed for themes. Results suggested that the particular image speed selected by an athlete does often serve a specific purpose. Slow-motion images were primarily employed to enhance the learning, development, review, or refinement of skills and strategies. Real-time imagery was employed when athletes wanted to accurately represent movement tempo, relative timing, or absolute movement duration in their images. Fast motion images were used to enable strategy planning during competition, to increase or maintain confidence perceptions, to energize athletes, and to increase imagery session efficiency and focus. Furthermore, regarding the use of multiple image speeds, athletes emphasized the importance of avoiding exclusively imaging in fast- or in slow-motion, making note of the importance of real-time image speed use in ensuring accurate mental representations of temporal aspects of performance. The findings of the current study indicate that the timing guideline of the PETTLEP approach to motor imagery (Holmes & Collins, 2001) may require revision. The use of any given image speed may be a matter of personal preference rather than one of functional necessity. One exception, however, does appear to be images focused on learning some temporal aspect of performance. In these instances, real-time speed seems to be a necessary characteristic of one’s image.

Imagery studies have varied widely in the methods used to deliver guided imagery interventions. This variation has led to difficulties comparing studies and uncertainty as to what methods should be followed. A review is needed to evaluate the interventions to date to inform applied recommendations. The aim of this systematic review was to (1) assess the quality of intervention design, (2) investigate the extent to which interventions vary, (3) highlight the different methods that should be considered in the design and implementation of future interventions, and (4) investigate adherence to some of the current theories and models of imagery use. A total of 20 interventions administered between the years 2001 and 2011 were compared over 17 main areas, including imagery ability, duration, script development, delivery method, and adherence to the PETTLEP model and the bio-informational theory. The results of this review found evidence of many inconsistencies between interventions and demonstrate a need for more comprehensive practical guidelines. Recommendations are offered for the design of future interventions, including increasing imagery practice time and the use of personalised imagery scripts. Numerous questions are raised to strengthen and direct future research such as the need for continued modification of scripts throughout an intervention.

Motor imagery and actual movement engage similar neural structures, however, whether they produce similar training-related corticospinal adaptations has yet to be established. The aim of this study was to compare changes in strength and corticospinal excitability following short-term motor imagery strength training and short-term strength training. Transcranial magnetic stimulation (TMS) was applied over the contralateral motor cortex (M1) to elicit motor-evoked potentials in the dominant biceps brachii muscle prior to and following 3-week strength training using actual bicep curls or motor imagery of bicep curls. The strength training ( n = 6) and motor imagery ( n = 6) groups underwent three supervised training sessions per week for 3 weeks. Participants completed four sets of six to eight repetitions (actual or imagined) at a training load of 80% of their one-repetition maximum. The control group ( n = 6) were required to maintain their current level of physical activity. Both training groups exhibited large performance gains in strength ( p < 0.001; strength training 39% improvement, imagery 16% improvement), which were significantly different between groups ( p = 0.027). TMS revealed that the performance improvements observed in both imagery and strength training were accompanied by increases in corticospinal excitability ( p < 0.001), however, these differences were not significantly different between groups ( p = 0.920). Our findings suggest that both strength training and motor imagery training utilised similar neural substrates within the primary M1, however, strength training resulted in greater gains in strength than motor imagery strength training. This difference in strength increases may be attributed to adaptations during strength training that are not confined to the primary M1. These findings have theoretical implications for functional equivalent views of motor imagery as well as important therapeutic implications.

Motor imagery (MI) used as mental preparation is known to be effective in enhancing athletic performance. However, data about the efficacy of mental preparation on performance and neuromuscular control of subsequent reactive movements are lacking. The purpose of the present study was to investigate the effects of MI on performance in drop jumps and on leg muscle activities. Fifteen participants performed maximal drop jumps from 26 cm height with and without kinesthetic MI in a randomized order. Ankle and knee angles, EMG of soleus, gastrocnemius, tibialis anterior, vastus medialis, biceps femoris and ground reaction forces were measured. Directly after MI participants showed a 3% ( p <0.05) higher performance index (PI = air time/ contact time) compared to control jumps. With regard to neuromuscular control participants showed higher preactivities (PRE = 100 ms before touchdown until touchdown) in soleus (11%, p <0.01) and in gastrocnemius (5%, p <0.05) muscles with MI compared to control jumps without MI. During the short latency response (30–60 ms after touchdown), muscle activities were enhanced in SOL and GAS (9%, p <0.01 and 8%, p <0.05, respectively). No differences were found for tibialis anterior, vastus medialis and biceps femoris. These findings indicate an enhanced neural drive directly after MI resulting in higher activation levels of triceps surae muscles before and shortly after touchdown. However, the effectiveness of using MI as mental preparation to enhance performance in drop jumps seems to be limited.

We asked the question, does motor simulation (via imagery) and planning with execution have similar intentional characteristics? And, does use of a tool compared to arm reaching influence a different intention effect? We instructed participants to use motor imagery to estimate distance reachability with the hand (arm extended) and a 20-cm tool using a NOGO/GO intention paradigm. That is, use of imagery only and imagery with actual execution (IE). Results indicated no differences in accuracy within or between HAND and TOOL conditions. That is, there was no observable intentional effect. These findings lend preliminary support to an increasing body of evidence suggesting that the neurocognitive processes (in this case, intention) driving motor imagery and executed actions are similar for hand and tool use.

: The benefits of imagery use have been shown for athletes and neurological patients, but little is known about the benefits of motor and exercise imagery for older adults. Current research on movement-related imagery is reviewed in this narrative article, with a focus on methods for estimating the ability to use motor and exercise imagery and the extent of their use. Recent investigations of motor imagery and exercise imagery in healthy older adults are reviewed. Recommendations for integrating the two approaches in future research are made and the potential of imagery use to encourage physical activity in older adults is discussed.