The purpose of this study was to determine if concentric velocities of lighter loads of could be augmented if they are performed heavier working sets. Twelve trained males with experience in the barbell back squat performed a 5RM and completed two separate squat training session conditions that consisted of three sets of five repetitions with 85% of their 5RM. Both conditions differed in the placement of a reduced-load set that was either performed after the working sets or during the warm-up period. No significant differences were observed in the working set MCVs in both conditions. Additionally, no significant differences were observed amongst MCVs in the Down Set and equivalent warm-up set loads. The results of this study suggest that postactivation potentiation may not occur using a similar set-load scheme.

The purpose of this study was to examine the relationship between estimated absolute and relative squat strength and a static jump protocol with potential to provide desirable training adaptation data to practitioners in the field of collegiate strength and conditioning. Forty-one young (20.80 ± 2.44 years), healthy volunteers reported estimated back squat 1RM’s based on the most recent training block and completed a static jump protocol. Males (n=19, est. 1RM 141.29 ± 32.02kg) and female (n=22, est. 1RM 71.56 ± 19.64kg) jump data revealed large to very large correlations between squat strength, mean jump heights of jumps and other calculated variables.

Title: The Analysis of the Effect of Weightlifting Shoes and Bare Feet Lifting on the Performance Measures of Back Squat. Objectives: The main goal of this study was to compare speed, power, and depth of the back squat performed both barefoot and in weightlifting shoes using the training protocol 5 × 5 (5 sets with 5 reps) at 70 % one-repetition maximum (1RM). Methods: Ten elite, male participants (27 ± 3.54 years old, 93 ± 10.23 kg of body weight, 179.28 ± 8.54 cm of height) were involved and assessed for the purposes of the study. All participants' 1RM back squat was not lower than 1.5 times of their body weight and they all had many years of experience using weightlifting as a part of their athletic development. The assessment was carried out at the training adaptation lab of the Department of Physiology and Biochemistry, the Faculty of Physical Education and Sport, Charles University in Prague (UK FTVS). Each participant followed the same training protocol during two sessions not less than 48 hours apart; the first one performed barefoot and the second one wearing the weightlifting shoes. Participants were asked to perform three repetitions, first with 20 % of their estimated 1RM, then with 40 % and 60 %, followed by two repetitions with 70 % and 80 % of their estimated 1RM to determine their...

Purpose: Young adolescent females are at the highest risk of sustaining an ACL injury, which may alter their movement and muscle activation patterns yet there is a lack sex- and age- specific guidelines for ACL injury management. The purpose of this study was to (1) evaluate the effects of limb dominance in a healthy uninjured population to serve as a baseline for the ACL-deficient cohort and (2) provide evidence of the neuromuscular patterns and biomechanical loading of uninjured and ACL-deficient knee joints in a female paediatric population. Methods: Eighteen active female adolescents with ACL rupture (ACLd) and 21 uninjured female adolescent controls matched for limb dominance (CON) participated in this study. Participants completed bilateral squats and drop vertical jumps (DVJ) while lower limb electromyography, kinetics and kinematics data were collected. Muscle synergies were extracted using a concatenated non-negative matrix factorization (CNMF) framework and compared between limbs, (CON dominant vs CON non-dominant and CON vs ACLd) across tasks and between limbs within tasks using intraclass correlation coefficients and statistical paramedic mapping. Results: ACLd participants took significantly longer to perform the squat relative to their uninjured peers. No significant differences were found for hip, knee and ankle peak joint flexion angles and moments between populations for the squat. Squat and DVJ muscle synergies were equivalent for dominant and non-dominant uninjured control limbs. ACL injured (ACL deficient and contralateral limbs) exhibited greater variability in DVJ synergy vectors than for the squat task. When comparing across tasks, scaling coefficients were consistently higher for the DVJ for all populations. Conclusion: Differences in lower limb kinematics, muscle activity and muscle activation patterns between dominant and non-dominant limbs indicate that limb symmetry, a clinical tool commonly used to assess rehabilitation and return to play may not provide relevant results. DVJ scaling factors were larger than those of the squat for all groups, likely due to the increased demand of that task. ACLd and CON participants completed squats and DVJ with similar lower limb joint angle patterns and muscle activity. ACL injured groups had fewer consistent vectors across tasks demonstrating greater variability in muscle activation patterns. This increased variability may be due to the ACL injury however, as injured participants were not studied pre- injury it cannot be confirmed.

The purposes of this investigation were to: (1) assess kinetic characteristics of overload, (2) examine eccentric and concentric muscle activations and (3) explore velocity measurement as a method of intensity prescription in inertial flywheel squat training. A series of two experiments were performed: one assessing kinetic and muscle activation characteristics of flywheel squat training using three progressive inertial loads. The second experiment assessed inertial load-velocity relationships using six progressive inertial loads. Peak force, net impulse, positive–negative impulse ratio and positive–negative impulse duration ratio were each statistically significant between all three load conditions (p < 0.05). Concentric vastus lateralis muscle activation was the only significant increase between inertial loads (p < 0.05). Although not statistically significant, concentric quadricep muscle activation was increased from the lowest to highest inertia. Conversely, eccentric quadricep muscle activation was reduced from the lowest to highest inertia. In the second experiment, statistically significant regression equations were observed for average concentric velocity (R2 = 0.66) and peak concentric velocity (R2 = 0.60). In conclusion, our results indicate (1) overload is possible kinetically, (2) phase-specific muscle activation responds differently to increased inertia and (3) velocity has the potential to be used for load prescription in the inertial flywheel squat.

Förmågan att generera kraft kan korrelera med individens prestationsförmåga i idrotter, sprint- och hoppträning kan gynna prestationsförmågan inom vissa idrotter. Syftet med denna studie var att undersöka huruvida det fanns korrelation mellan prestation i 5RM knäböj med skivstång och enbenslängdhopp. Vidare undersöktes även hur 5RM relaterat till kroppsvikt påverkade hopplängd, skillnader mellan män och kvinnor och skillnad i hopplängd mellan dominant och ickedominant ben. Totalt 37 motionärer rekryterades, 15 kvinnor och 22 män (35 ± 11 år), alla var erfarna av knäböj med skivstång. Deltagarna fick efter uppvärmning utföra en maxprestation i horisontella enbenshopp, vila 8 minuter och hitta sitt 5 RM i knäböj. Resultatet visade på svag positiv, statistiskt signifikant korrelation mellan hopplängd och muskelstyrka mätt i 5 RM knäböj (r= 0,4 p&lt;0,05), samt svag icke signifikant korrelation (r= 0,21, p&gt;0,05) då hänsyn till kroppsvikt togs.  Män hoppade 310,2 ± 39,6 cm vilket var signifikant (p&lt;0,05) längre än kvinnor som hoppade 266,3 ± 47,3 cm, mellan dominant och ickedominant ben visades ingen signifikant skillnad i hopplängd. Resultaten visade på ett signifikant svagt samband mellan 5 RM knäböjtest och enbenstest för hoppförmåga. Resultaten kan tolkas som att testen mäter olika fysiska förmågor dock har muskelstyrkan betydande inverkan på hoppförmågan. / The performance in sports may be determined by the ability to generate power. Sprinting and jumping in training can be beneficial to the athletes´ ability to perform explosive type of sports. The aim of this study was to examine the relationship between single leg hop for distance and a) back squat strength, 5 Repetition Maximum and b) back squat 5 Repetition Maximum correlated to body weight. A secondary aim was to examine the hop performance of dominant and non-dominant leg between males and females. 37 recreational individuals participated in the study, 15 women and 22 men (35 ±11years), all subjects were used to squatting. After warm up, the subjects were told to make a single leg hop for max distance, (3 tries) rest 8 minutes before squatting up to a 5 RM back squat.  The results showed that there was a positive correlation between total jump length (right + left leg) and 5 RM max weight (r= 0,4 p&lt;0,05) and a significant difference in total jump length between males and females (p&lt;0,05) but no difference in jump length between dominant and non-dominant leg between the subjects. Participants´ familiarity of jumping activities may have influence the outcome of this study.

The purpose of this study was to compare differences in maximal strength, perceived recovery and stress state, and body composition alterations in powerlifters undergoing a 2-day or 4-day period of training cessation following a step taper. Ten participants completed a 6-week powerlifting specific training protocol. Body composition, perceived recovery and stress state, and maximal strength in the back squat (BS), bench press (BP), and deadlift (DL) were assessed prior to the overreach week (week 5) and either 2-days or 4-days after the taper. Alpha criterion was set at p≤0.05. There were statistically significant increases in BP (pp=0.03) following the 2-day protocol. Following the 4-day protocol, there were statistically significant increases in DL (p=0.03) and statistically significant decreases in BP (p=0.04). The results of this study support the use of shorter periods of training cessation (i.e., two days) following a step taper to improve maximal strength performance.

1 ABSTRACT Title: Comparing physiotherapist's functional test assessments with OpenPose kinematic data Objectives: Assess wether is OpenPose (OP) system able to detect parameters of poor performance in the Single Leg Squat Test and Step Down Test. Presence of these parameters was indicated by consensus process among 3 physiotherapists. Methods: 48 healthy volunteers participated on the research. Each volunteer demonstrated 3 repetitions of Single Leg Squat Test and Step Down Test on each leg. Repetitions were recorded on video and at the same time evaluated by 3 physiotherapists (PT) using 15 binary parameters. Consensus process indicating presence of a parameter involved agreement of at least 2 of the raters while the inter-rater reliability coeficient for all 3 raters had to be κ ≥ 0,41. Changes in angles and relative distances of observed body segments were calculated using OpenPose keypoint detection model. Therefore each execution of the functional test was described by OP data and PT data. Statistical analysis was performed to assess wether was OpenPose able to detect significant differences between poor and good execution of a functional test in the 15 rated parameters. Results: OP was able to reliably assess following parameters: Loss of balance, Excessive upper extremity movement and Lateral...

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The purpose of this study was to determine the differences in kinetic, kinematic, and metabolic variables between an acute normal dead stop squat (NDS) protocol and an acute accentuated eccentric loaded squat (AEL) protocol. Eight collegiate weightlifters were performed the 2 squat protocols. Eccentric and concentric kinetic and kinematic data were collected via synchronized force plate and linear position transducer. Metabolic parameters assessed were oxygen consumption (VO2 ) using open circuit spirometry, testosterone (T) and cortisol (C) via blood draw from antecubital vein, and lactate (La) values via finger prick blood draw. The following are major findings of the dissertation. No statistical differences were observed for concentric variables between AEL and NDS work sets or between warm-up at 55% (WUP55) and postset at 55% (POST55) sets. Differences were found in the speed and duration of the eccentric portion of the lifts. Results indicate that there are no meaningful biomechanical differences when performing AEL squats in this manner and that the intensity and volume executed did not result in PAP. Oxygen uptake was statistically different during sets with the additional eccentric load (set 4, 5, 6, 7) and the subsequent down set (set 9). Lactate was greater during AEL squatting than NDS after set 7 and set 8 for the whole group. T exhibited no statistically significant changes. C was greater immediately following the AEL protocol compared to NDS 30 minutes post-AEL squat protocol yielded a statistically significant difference from immediately post and a return to near baseline measures. These acute changes may have meaningful effects on long- term gains in hypertrophy and strength. The findings of this dissertation show the potential benefits of AEL dead-stop squats for long-term hypertrophy and strength development. However, because this dissertation was the first to explore dead-stop squats with an additional eccentric load, further research is required on both the potential benefits of dead-stop squats and typical squats with no dead-stop using an AEL protocol.