Purpose: To establish whether measurements obtained from the isometric mid-thigh pull (IMTP) or isometric squat (ISQT) relate to performance of a dynamic one-repetition maximum (1RM) for the barbell back squat. Methods: Eight resistance trained men (22.9±3.7yrs; 177.3±5.7cm; 84.9±17.4kg; 1RM: 1.89 ± 0.29x body weight) completed two separate visits: a preliminary visit, during which participants completed a 1RM of the back squat, and IMTP and ISQT familiarization. At least 72 hours later (Day 2) participants completed the IMTP and ISQT. Prior to all testing, participants cycled for 5-minutes at a submaximal intensity followed by 10 bodyweight squats and 10 walking lunges. Briefly, participants were fitted for the IMTP at 110° at the hip and at 75% of their standing stature for ISQT. Participants completed 3 maximal effort, 6-second attempts of both IMTP and ISQT, with each attempt separated by 3 minutes of seated rest. Isometric force and rate of force development (RFD) were recorded at 1,000Hz, and correlated with 1RM values with a Pearson Product Moment Correlation. Results: A significant positive correlation was observed between the peak RFD of ISQT and 1RM load (r=0.746, p=0.034). No other significant correlations were observed between force production or RFD for IMTP or ISQT. Conclusions: The peak RFD for ISQT had the greatest relationship with 1RM, however, the results of this project are preliminary and likely require data larger sample size.
Purpose: To observe the effect of wearing knee wraps on passive isometric torque production at varying degrees of knee flexion. Methods: Nine recreationally active men (22.9 ± 3.7 yrs; 177.3 ± 5.7 cm; 84.9 ± 17.4 kg) completed one experimental visit. Prior to testing, participants’ height, weight, body composition (13.9 ± 7.0%) and knee circumference (37.8 ± 2.0 cm) were recorded. Participants then completed a one-repetition maximum (1-RM) in the back squat and were considered to be resistance trained after completing a 1-RM of at least 1.5x their body weight. Qualified participants then performed passive isometric force tests on their right leg using a HUMAC Isokinetic Dynamometer. Forces were recorded at 100Hz for nine different angles (70° - 110° at 5° increments, lasting 5 seconds each): two with the right knee wrapped (KW), and two unwrapped (UW). Knee wrap trials were separately wrapped between attempts. Data were analyzed via within-subjects repeated measures ANOVA. Results: A significant condition x angle interaction was observed (F=218.677; p≤0.0001, ηp2 =0.965). Post hoc analyses revealed significant differences between all angles for KW (p≤0.005), and between angles greater than 90° for UW (p≤0.05). Paired samples t-tests revealed significantly greater force production in KW compared to UW at all angles (p≤0.05) excluding 70°(p=0.205). Conclusion: Applying knee wraps significantly increases passive isometric forces at angles greater than 70° of knee flexion when compared to the unwrapped condition. Furthermore, knee wraps produce greater forces as the angle of flexion increases.
Hematological Effects of a Mechanical aid on Muscular Performance and Recovery following Resistance Exercise04/09/2019
Hematological Effects of a Mechanical aid on Muscular Performance and Recovery following Resistance Exercise
1Tasia A. Doshak, 1Brandon M. Gibson, 1Joseph A. Laudato, 1Cody S. Dulaney, 1Emily C. Tagesen, 2Cardyl P. Trionfante, 1Adam R. Jajtner
1Exercise Physiology Program, Kent State University, Kent, OH
2Department of Kinesiology and Health, University of Miami, Oxford, OH
PURPOSE: To examine the leukocyte response to an acute squat protocol while wearing knee wraps versus no knee wraps. METHODS: 7 resistance trained men (22.3±3.6 yrs, 69.1±1.12 in, 77.9±5.4 kgs BW; 1-RM = 153.3±26.8 kgs) completed four experimental visits. Participants were asked to complete 8 sets of 10 repetitions of the squat at 70% of their 1-RM. Blood samples were collected prior to exercise (PRE), as well as immediately (IP), one hour(1H), 24 hours (24H) and 48 hours (48H) after exercise. Blood samples were analyzed via hematology analyzer for leukocyte count (WBC), lymphocyte (LY), monocyte (MO) and granulocyte (GR) number (#) and ratio (%). Data were analyzed using a condition x time repeated measures ANOVA. RESULTS: Significant main effects of time were observed for LY% (pp2=0.1800), LY# (pp2=0.923), MO# (pp2=0.652), GR% (pp2=0.793) and GR# (pp < 0.05), while GR% was reduced at IP compared to PRE, 1H and 24H (pp < 0.05) compared to PRE, 24H, and 48H. GR% and GR# were also both greater at 24H versus 48H values (pp=0.013). CONCLUSIONS: Resistance exercise elicits an immediate increase in circulating leukocytes, primarily through increases in LY%.