Exercise regulation (pacing) in strength training

  • Peter Ibbott

Student thesis: Master's Thesis


The purpose of this thesis was to investigate the effect of self-selected rest periods on strength training performance when experienced strength-trained athletes were provided the opportunity to select the rest period between sets of a heavy back squat exercise. To date, minimal research exists with regard to self-regulation (pacing) of rest periods during strength training; the majority of research surrounding rest periods in strength training focuses on imposed rest periods and their effect on training volume. Recently, research has begun to compare the differences in training outcomes between self-selected rest periods and imposed rest periods utilising moderate loads in subjects from the general population. It is believed that an understanding of how experienced strength-trained athletes approach heavy strength training when afforded the opportunity to select their rest periods between sets of a heavy back squat will allow coaches to better plan and implement strength training programs. Sixteen experienced strength-trained male athletes (mean age = 22.8 ± 3.1 a) completed a familiarisation self-selected rest trial followed by two self-selected rest trials (SS), one 3 min rest trial (3M) and one 5 min rest trial (5M). The trials were conducted in random order over a 14 day period with a minimum of 48 h between each trial. Each trial consisted of five sets of 5 repetition max (RM) back squats interspersed with the specific rest period for that trial. A GymawareTM optical encoder collected kinetic data for each squat and temporal data for each inter-set rest period. Surface electromyography (sEMG) data for the vastus medialis oblique (VMO), vastus lateralis (VL) and biceps femoris (BF) muscles of the right leg was collected and analysed using a portable wireless bio-amplifier system, with all trials recorded at 1000 Hz. Subjective measures of readiness to lift (RTL) and rating of perceived effort (RPE) were taken before and after each set. The first study investigated the consistency of strength-trained athletes in regulating self-selected rest periods between sets of heavy squat training to maintain performance. Analysis of the data showed that participants demonstrated similar between-set kinetic performance and subjective responses on different days. However, a significant difference was observed between self-selected trial power output (SS1 850 ± 133 W; SS2 831 ± 110 W) and inter-set rest periods for sets 3 (95% CI = [-83; -17]), 4 (95% CI = [-101; -35]) and 5 (95% CI = [-96; -29]), compared to set 1 irrespective of trials, suggesting rest periods were regulated to maintain performance in response to inter-daily biological variation. The second study compared the kinetic, neuromuscular and psychological responses between the SS and the imposed 3M and 5M trials of strength-trained athletes. Linear mixed modelling revealed that during the SS trial, rest periods increased from sets 1 to 3 with self-selected rest periods prior to the 4 and 5 sets being between three and five min. For the imposed rest period trials, performance across sets 3, 4 and 5 deteriorated when compared to that of set one. For the SS trial, performance across sets 3 and 4 deteriorated when compared to that of set 1. Surface EMG was similar across all trials and sets, suggesting performance decline could be more attributed to peripheral rather central fatigue. A significant main effect of condition (p<0.001), indicated that participants reported to feel better prepared to lift in the 5M trial compared to the 3M and SS trials. The findings from this research provide strength and conditioning coaches and academics with an opportunity to implement and refine self-selected rest strategies in strength training. Coaches should look to utilise these methods with experienced strength-trained athletes, after an appropriate period of familiarisation, to supporting the manipulation of program design to improve training efficiency and performance without impacting on other training modalities. Future studies of this nature should have multiple familiarisation trials and extremely detailed instructions given to participants to ensure valid and reliable data is gathered for analysis. The results from this study are seen as a good basis for which to extend research and knowledge in this field.
Date of Award2018
Original languageEnglish
SupervisorKevin Thompson (Supervisor), Nick Ball (Supervisor) & Keane Wheeler (Supervisor)

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