INTRODUCTION: Resistance exercises are effective for maintaining health and activating stabilizing muscles, as they trigger abdominal wall tension responses. This study compared the effects of multi-joint and single-joint, upper-body and lower-body exercises (Lat pulldown, Rows, Peck deck, Chest press, Biceps curls, Triceps extensions, French-Press, Step up, Hip abduction/adduction, Squat, Leg press, Romanian deadlift, Hamstring curls) performed at maximal and submaximal intensities. METHODS: This cross-sectional study included 12 men and 18 women (age:47.8 ± 5.9 years, height:174.8 ± 10.2 cm, weight: 77.7 ± 15.4 kg, BMI:25.3 ± 3.6), who wore a noninvasive sensor Ohmbelt to measure abdominal wall tension performing exercises at 15 repetition maximum (RM), 10RM, 5RM, and 1RM. Differences across exercises and sex were compared by Friedman test with Durbin-Conover post-hoc, and intensities were analyzed by Wilcoxon test. RESULTS: The study found significant differences (p < 0.05) in abdominal wall tension changes based on the type of exercise and training intensity. Multi-joint lower-body exercises, such as the Romanian deadlift, dumbbell front squat, and leg press, led to the greatest increases in abdominal tension in both sexes in comparison to single-joint upper-body exercises. Males had higher abdominal wall tension changes than females (p < 0.05) at 1RM, 5RM, and 10RM. However, no significant difference was found at 15RM, indicating that lower intensities produce similar abdominal wall tension changes in both sexes. CONCLUSIONS: This study showed that multi-joint lower-body exercises were found to produce greatest abdominal wall tension increases, especially compared to single-joint upper-body exercises. The abdominal wall tension was higher in males than females due to higher loads, emphasizing the need for exercise-specific approaches.

• Keywords
• Exercise prescription, Intra-abdominal pressure, Muscle activation, Noninvasive monitoring, Resistance exercise,
• Publication type
• Journal Article MeSH

BACKGROUND: Abdominal bracing is a maneuver widely used by rehabilitation specialists and sports trainers to improve spinal stability. This study aimed to investigate how lifting tasks with and without abdominal bracing affect the respiratory function of the diaphragm. METHODS: M-mode ultrasonographic assessment of diaphragmatic motion combined with spirometry was performed on 31 healthy adults. Participants were asked to breathe continuously whilst lifting a load with spontaneous abdominal muscle contraction (natural loaded breathing) and abdominal bracing (AB loaded breathing). RESULTS: Pearson's correlations revealed strong correlations between ultrasonography and spirometry measures (p < 0.001) for all types of breathing: tidal breathing (r = 0.709, r2 = 0.503), natural loaded breathing (r = 0.731, r2 = 0.534) and AB loaded breathing (r = 0.795, r2 = 0.632). Using paired-samples t-tests, the natural loaded breathing ultrasonography revealed more caudal diaphragm positions during inspiration (p < 0.001) but not during expiration (p = .101). Spirometry demonstrated lower lung volumes (L) at the end of inspiration and expiration (p < 0.001), with no changes in total lung volume (p = 0.06). The AB loaded breathing ultrasonography revealed more caudal diaphragm positions during inspiration (p = 0.002) but not during expiration (p = 0.05). Spirometry demonstrated lower lung volumes at the end of inspiration (p < 0.001), expiration (p = 0.002), and total lung volumes (p = 0.019). CONCLUSION: This study demonstrated that abdominal bracing performed during a lifting task reduces lung volume despite an increase in diaphragmatic motion. Diaphragm excursions strongly correlate with lung volumes even under postural loading. TRIAL REGISTRATION: The study was prospectively registered on 8 April 2021 at ClinicalTrials.gov with identification number NCT04841109.

• Keywords
• Abdominal bracing, Breathing, Diaphragm, M-mode ultrasonography, Spinal stabilization,
• Publication type
• Journal Article MeSH

OBJECTIVES: The diaphragm changes position and respiratory excursions during postural loading. However, it is unclear how it reacts to lifting a load while breath-holding or breathing with simultaneous voluntary contraction of the abdominal muscles (VCAM). This study analyzed diaphragm motion in healthy individuals during various postural-respiratory situations. METHODS: 31 healthy participants underwent examination of the diaphragm using M-mode ultrasonography, spirometry, and abdominal wall tension (AWT) measurements. All recordings were performed simultaneously during three consecutive scenarios, i.e., 1. Lifting a load without breathing; 2. Lifting a load and breathing naturally; 3. Lifting a load and breathing with simultaneous VCAM. RESULTS: Using paired-samples t-tests, lifting a load without breathing displaced the diaphragm's expiratory position more caudally (P < .001), with no change noted in the inspiratory position (P = .373). During lifting a load breathing naturally, caudal displacement of the diaphragm's inspiratory position was presented (P < .001), with no change noted in the expiratory position (P = 0.20) compared to tidal breathing. Total diaphragm excursion was greater when loaded (P = .002). Lifting a load and breathing with VCAM demonstrated no significant changes in diaphragm position for inspiration, expiration, or total excursion compared to natural loaded breathing. For all scenarios, AWT measures were greater when lifting a load (P < .001). CONCLUSION: In healthy individuals, caudal displacement and greater excursions of the diaphragm occurred when lifting a load. The postural function of the diaphragm is independent of its respiratory activity and is not reduced by the increase in AWT.

• MeSH
• Diaphragm * diagnostic imaging   physiology   MeSH
• Respiration * MeSH
• Humans MeSH
• Muscle Contraction MeSH
• Ultrasonography MeSH
• Exhalation MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH