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  1. Article ; Online: Comparison of drop jump force-time profiles of team sport athletes and active controls

    Thomas Scarr / Dustin J Oranchuk / Daniel Rafferty

    Motriz: Revista de Educacao Fisica, Vol

    2021  Volume 27

    Abstract: Abstract Aim: Lower-body non-contact injuries in team sport athletes (TSAs) are associated when absorbing force, during cutting and landing movements due to a lack of eccentric strength and decreased neuromuscular control leading to excessively higher ... ...

    Abstract Abstract Aim: Lower-body non-contact injuries in team sport athletes (TSAs) are associated when absorbing force, during cutting and landing movements due to a lack of eccentric strength and decreased neuromuscular control leading to excessively higher joint forces. Thus, this project aimed to identify if TSAs had different acceleration and deceleration force profiles compared to a control group (non-TSA) when performing drop jumps (DJs). Methods: University TSAs (n = 15) and non-TSAs (n = 10) performed a series of DJs from a 39 cm box onto a force-plate. All data were normalized to the individual's body mass. Between-group differences in ground reaction force (GRF), rate of force development (RFD), and propulsive and breaking impulses were compared via t-tests and standardized differences. Results: TSAs had significantly, and meaningfully greater RFD than the non-TSAs (p < 0.01, Hedges’ g (ES) = 1.24, 53%). While not statistically significant, the non-TSA group produced practically larger mean GRFs than TSAs (p = .09, ES = 0.72, 12.1%). No significant or meaningful between-group differences were detected for propulsive impulse (p = 0.08, ES = 0.41, 9.1%), braking impulse (p = 0.85, ES = 0.25, 4.6%), or impulse ratio (p = 0.35, ES = 0.21, 6.7%). Conclusions: This study shows the presence of significant RFD differences during the DJ in TSAs compared to non-TSAs. Furthermore, this investigation also showed there was no difference between TSA and students in GRF and impulse metrics. Implications from these findings suggest that TSAs can produce force rapidly, but deceleration metrics were not different from untrained students.
    Keywords eccentric ; force plate ; impulse ; landing ; mechanics ; rate of force development ; Sports ; GV557-1198.995 ; Sports medicine ; RC1200-1245
    Subject code 796
    Language English
    Publishing date 2021-11-01T00:00:00Z
    Publisher Universidade Estadual Paulista (UNESP)
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: Effect of Small and Large Energy Surpluses on Strength, Muscle, and Skinfold Thickness in Resistance-Trained Individuals

    Eric R. Helms / Alyssa-Joy Spence / Colby Sousa / James Kreiger / Steve Taylor / Dustin J. Oranchuk / Brad P. Dieter / Casey M. Watkins

    Sports Medicine - Open, Vol 9, Iss 1, Pp 1-

    A Parallel Groups Design

    2023  Volume 14

    Abstract: Abstract Background Many perform resistance training (RT) to increase muscle mass and strength. Energy surpluses are advised to support such gains; however, if too large, could cause unnecessary fat gain. We randomized 21 trained lifters performing RT 3 ... ...

    Abstract Abstract Background Many perform resistance training (RT) to increase muscle mass and strength. Energy surpluses are advised to support such gains; however, if too large, could cause unnecessary fat gain. We randomized 21 trained lifters performing RT 3 d/wk for eight weeks into maintenance energy (MAIN), moderate (5% [MOD]), and high (15% [HIGH]) energy surplus groups to determine if skinfold thicknesses (ST), squat and bench one-repetition maximum (1-RM), or biceps brachii, triceps brachii, or quadriceps muscle thicknesses (MT) differed by group. COVID-19 reduced our sample, leaving 17 completers. Thus, in addition to Bayesian ANCOVA comparisons, we analyzed changes in body mass (BM) with ST, 1-RM, and MT changes via regression. We reported Bayes factors (BF10) indicating odds ratios of the relative likelihood of hypotheses (e.g., BF10 = 2 indicates the hypothesis is twice as likely as another) and coefficients of determination (R 2) for regressions. Results ANCOVAs provided no evidence supporting the group model for MT or squat 1-RM. However, moderate (BF10 = 9.9) and strong evidence (BF10 = 14.5) indicated HIGH increased bench 1-RM more than MOD and MAIN, respectively. Further, there was moderate evidence (BF10 = 4.2) HIGH increased ST more than MAIN and weak evidence (BF10 = 2.4) MOD increased ST more than MAIN. Regression provided strong evidence that BM change predicts ST change (BF10 = 14.3, R 2 = 0.49) and weak evidence predicting biceps brachii MT change (BF10 = 1.4, R 2 = 0.24). Conclusions While some group-based differences were found, our larger N regression provides the most generalizable evidence. Therefore, we conclude faster rates of BM gain (and by proxy larger surpluses) primarily increase rates of fat gain rather than augmenting 1-RM or MT. However, biceps brachii, the muscle which received the greatest stimulus in this study, may have been positively impacted by greater BM gain, albeit slightly. Our findings are limited to the confines of this study, where a group of lifters with mixed ...
    Keywords Resistance training ; Body composition ; Hypertrophy ; Energy surplus ; Sports medicine ; RC1200-1245
    Subject code 796
    Language English
    Publishing date 2023-11-01T00:00:00Z
    Publisher SpringerOpen
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: The acute hypotensive effect of resistance training performed with machines vs free weights in normotensive men

    Bruno V. C. da Silva / Mário A. M. Simim / Lorena Carolina Reis Viegas / Thaís Soares Brígido / Ronaldo Ângelo Dias da Silva / Dustin J. Oranchuk / Gustavo Ribeiro da Mota

    Motriz: Revista de Educacao Fisica, Vol 24, Iss

    2018  Volume 2

    Abstract: Abstract AIMS To analyze if different resistance training (machine vs free weight) would have different acute hypotensive effect in active and normotensive individuals. METHODS Fifteen male volunteers (39.2±2.5 years) performed two different resistance ... ...

    Abstract Abstract AIMS To analyze if different resistance training (machine vs free weight) would have different acute hypotensive effect in active and normotensive individuals. METHODS Fifteen male volunteers (39.2±2.5 years) performed two different resistance exercise protocols, one on machinery and one with free weights for the similar muscle groups and volume (sets x repetitions). Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured at rest and during 60 minutes after the sessions. RESULTS There was no interaction between (treatments vs time) for SBP (F 70, 84 = 0.9445, p = 0.595) and DBP (F 70, 84 = 0.5743, p = 0.991). However, significant differences for time for SBP (F 14, 84 = 7.058, p = 0.001) and DBP (F 14, 84 = 3.296, p = 0.001), and treatment for SBP (F 5, 6 = 291.1, p = 0.001) and DBP (F 5, 6 = 13.29, p = 0.003) were varified. CONCLUSION Our findings indicate that both resistance training (machine or free weight) induce a similar hypotensive response for SBP in normotensive men.
    Keywords systolic blood pressure ; strength training ; diastolic blood pressure ; Sports ; GV557-1198.995 ; Sports medicine ; RC1200-1245
    Subject code 796
    Language English
    Publishing date 2018-09-01T00:00:00Z
    Publisher Universidade Estadual Paulista (UNESP)
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    Full text online

    More links

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    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

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