(3) ASSESSING THE EFFECTS OF A TRADITIONAL KETTLEBELL SWING AND MODIFIED ISOMETRIC KETTLEBELL HOLD ON MUSCLE CONTRACTILITY AND PRESSURE PAIN THRESHOLDS

 

Purpose: A kettlebell swing may activate the posterior lumbopelvic musculature and induce a decrease in pain sensitivity through a concept referred to as exercise induced hypoalgesia (EIH).  While changes in muscle contractility and pressure pain threshold (PPT) in the posterior lumbopelvic musculature is likely to occur with sufficient dosing, the extent of these changes is not clear.  The aim of this study is to examine the acute effects of a modified Tabata style kettlebell swing workout on posterior lumbopelvic muscle PPT and contractility.

Methods: Forty, recreationally active participants [(27 males and 13 females, average age = 23.85 (SD = +- 2.726), average body mass = 73.66 kg. (SD = +- 13.01) and height = 174.287 cm (SD = +-12.448)], were randomized into one of three groups: Control, Russian style kettlebell swing, or isometric hold in the initial position of a kettlebell swing. Those placed in the kettlebell swing or isometric hold groups were first familiarized with their assigned exercise protocol, followed by a standardized warm up. Tensiomyography (TMG) was used to measure the contractility of the erector spinae (ES), gluteus maximus (GM), and biceps femoris (BF) due to research evidence supporting the role of these muscles in the kettlebell swing. Handheld pressure algometry measured PPT of ES, piriformis (PF), and quadratus lumborum (QL) due to their relevance in lumbosacral pathologies, making these muscles potential targets for a potential EIH effect. Participants then completed their assigned exercise in an interval-style format, (30 sec on/off for 10 intervals). PPT and contractility measurements were taken before and after completion of the assigned intervention. A mixed model ANOVA examined for group x time interactions.

Results: Groups did not significantly differ at baseline based on TMG (ES: p=.645 GM: p=0.733, PF: p=.586) and PPT measurements (ES: p=.232, QL: p=.425, PF: p=.386) Group x time interactions were not significant for PPT or TMG variables (p > .05). Within-group differences were found for both the kettlebell swing group (p=.017) and isometric hold group (p=.015) for PPT of the PF. PPT significantly increased, indicating decreased tenderness at the PF after completing kettlebell swing and isometric contractions.  No other significant within group differences were observed.

Conclusions: The isometric hold may be an effective alternative to the kettlebell swing in decreasing PPT in the PF. This may be of value among individuals unable to perform a traditional kettlebell swing.

PRACTICAL APPLICATIONS: This is the first study to examine differences in both TMG and PPT measurements after a modified Tabata-style protocol. Since the isometric hold and kettlebell swing groups elicited similar within-group differences in PPT for the PF, the isometric hold may be an option to induce EIH in this muscle group without the high exercise intensity of a typical Tabata-style protocol. This finding demonstrates the potential of the isometric hold to be used as an alternative to the kettlebell swing, especially for those with medical conditions contraindicating high-intensity exercise.

Acknowledgements: None