Abstract
Resistance exercise (RE) with blood flow restriction (BFR) promotes muscle hypertrophy, using low external loads and may also improve cognitive function and neuroplasticity, possibly by increasing brain-derived neurotrophic factor (BDNF). Lactate accumulation during exercise has been proposed as a potential mediator of exercise-induced increases in BDNF. However, it is unclear whether different RE loading strategies or BFR under fatigue-matched conditions produce distinct lactate responses that could differentially influence downstream neurotrophic mechanisms. PURPOSE: This study examined blood lactate responses for high-load (HL), low-load (LL), and LL-BFR RE in recreationally active young adults. METHODS: Sixteen healthy, recreationally active young adults (8 males, age: 25 ± 4.4; height: 168.7 ± 9.5 cm; weight: 74.8 ± 17.3 kg) completed three experimental Smith machine squat conditions in a randomized, counterbalanced, repeated-measures design: HL, LL, and LL-BFR. HL was performed at 70% one-repetition maximum (1RM), whereas LL and LL-BFR were performed at 30% 1RM. During the LL-BFR condition, cuff pressure was set at 40% of resting arterial occlusion pressure determined using ultrasonography. Each condition consisted of four sets performed to volitional failure, with 1 minute of rest between sets. Venous blood lactate was collected before (pre) and immediately after exercise (post). One-way repeated-measures ANOVAs was used to compare change in lactate concentration (post-pre) and total exercise volume (repetitions × load) between conditions. Effect sizes were reported as partial eta squared (η²ₚ). RESULTS: There was no significant main effect of condition for the change in blood lactate concentration (F = 2.50, p = 0.10, η²ₚ = 0.143). Mean (± SD) lactate changes were 6.15 ± 2.78 mmol·L-1 for LL, 5.36 ± 3.51 mmol·L-1 for HL, and 5.23 ± 2.68 mmol·L-1 for LL-BFR. However, exercise volume differed significantly among conditions (F = 14.61, p < 0.001, η²ₚ= 0.493), with the greatest volume during LL (6809 ± 2478), followed by LL-BFR (5979 ± 2340), and the lowest volume during HL (4629 ± 1793) (all p < 0.05). CONCLUSION: When resistance exercise conditions are completed to volitional fatigue, blood lactate responses do not differ among HL, LL, and LL-BFR squats despite differences in total exercise volume. This may indicate that mechanisms other than lactate-driven metabolic stress may contribute to the distinct physiological responses with BFR, especially when fatigue is similar. Overall, these findings suggest that practitioners may have flexibility in selecting load and using BFR when prescribing metabolically stressful resistance exercise aimed at promoting favorable adaptations, including those potentially related to cognitive function and neuroplasticity.
Recommended Citation
Song, Jiwon; Pennartz, Kase; Lee, Wonjae; Deemer, Sarah; Vingren, Jakob; Church, David; and Keller, Joshua L.
(2026)
"Fatigue-Matched Three Different Squats Elicit Blood Lactate Responses in Young Adults,"
International Journal of Exercise Science: Conference Proceedings: Vol. 2:
Iss.
18, Article 57.
Available at:
https://digitalcommons.wku.edu/ijesab/vol2/iss18/57
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Health and Physical Education Commons, Medical Education Commons, Sports Sciences Commons