This study aimed to determine the validity and between-day reliability of the mean velocity (MV), peak velocity (PV), mean power (MP), and peak power (PP) provided by the Vitruve linear position transducer at different submaximal loads in the free-weight and Smith machine back squat using GymAware as a reference point. Fourteen male sports science students (free-weight back squat one-repetition maximum [1RM]: 132.5 ± 28.5 kg, Smith machine back squat 1RM: 163.9 ± 30.4 kg) performed six experimental sessions, twice per week with 72 hours of rest. The first two included the assessment of the 1RM of both exercises. In the four remaining, both linear position transducers were simultaneously used to record MV, PV, MP, PP of each repetition during an incremental load test (i.e., 20, 40, 60, 80, 90% 1RM) with three minutes of rest between sets. Vitruve displayed both fixed and proportional bias for certain relative loads across all variables. Vitruve did not meet the validity criteria for all (MV, PP) or at least two (MP, PV) relative loads (Coefficient of variation [CV] > 10%; Pearson correlation < 0.70; Effect size > 0.60). MV, PV, MP, and PP recorded by Vitruve displayed acceptable reliability (CV < 10%) with superior reliability observed during a Smith Machine compared to free-weight back squat, and for velocity compared to power variables. Considering GymAware as a reference point, Vitruve was not valid for measuring velocity and power outcomes. Acceptable validity was observed only for PV in the Smith machine back squat, while the other variables—regardless of relative loads and exercise modes—were mostly inaccurate. All variables demonstrated acceptable reliability, with greater reliability noted in the Smith machine compared to the free-weight back squat exercise mode.

This study aimed to compare the between-session reliability of different performance variables during 2 variants of the Smith machine back-squat exercise. Twenty-six male wrestlers performed 5 testing sessions (a 1-repetition maximum [1RM] session, and 4 experimental sessions [2 with the pause and 2 with the rebound technique]). Each experimental session consisted of performing 3 repetitions against 5 loads (45–55–65–75–85% of the 1RM). Mean velocity (MV), mean power (MP), peak velocity (PV), and peak power (PP) variables were recorded by a linear position transducer (GymAware PowerTool). The best and average scores of the 3 repetitions were considered for statistical analyses. The coefficient of variation (CV) ranged from 3.89% (best PV score at 55% 1 RM using the pause technique) to 10.29% (average PP score at 85% 1 RM using the rebound technique). PP showed a lower reliability than MV, MP, and PV (CV_ratio ≥ 1.26). The reliability was comparable between the exercise techniques (CV_ratio = 1.08) and between the best and average scores (CV_ratio = 1.04). These results discourage the use of PP to assess back-squat performance at submaximal loads. The remaining variables (MV, MP, or PV), exercise techniques (pause or rebound), and repetition criteria (best score or average score) can be indistinctly used due to their acceptable and comparable reliability.

This study explored the goodness-of-fit and the effect of fatigue on the precision of both generalized and individualized relationships between the velocity loss (%VL) magnitude and the percentage of completed repetitions with respect to the maximal that can be performed to failure (%Rep) in the Smith machine parallel back-squat exercise. Twenty-nine resistance-trained males completed four sets to failure, with a rest period of 2 min, against 75% of the one-repetition maximum. Generalized and individualized %Rep-%VL equations determined in the first set were used to estimate %Rep when a 20%VL was achieved during the three successive sets. Individualized %Rep-%VL relationships (R² = 0.84–0.99) showed a greater goodness-of-fit than the generalized %Rep-%VL relationship (R² = 0.82). However, the accuracy in the %Rep estimation was always low (absolute errors > 10%) and comparable for both regression models (p = 0.795). %Rep was progressively overestimated when increasing the number of sets using the MV_fastest of the first set (from 15% to 45%), but no meaningful overestimations were observed using the MV_fastest of each set (~2%). In conclusion, neither the generalized nor the individual %Rep-%VL equations provide accurate estimations of %Rep during the parallel back-squat exercise executed under fatigue.

The aim of the research was to examine the sensitivity of load-velocity (L-V) relationship parameters (L₀, v₀, and A_line (area under the L–V line; A_line = L₀× v₀/ 2)) in detecting fatigue after different fatigue protocols as well as their correlation with changes in 1-repetition maximum (1RM). After a familiarization and preliminary testing session which was used for 1RM smith-machine squat (SMS) determination and performing a set of repetition to failure with 70%1RM load, 28 resistance-trained men randomly performed three fatigue protocols. All fatigue protocols were carried out between two incremental loading tests, conducted at the beginning (pre-session) and end (post-session) of the training session. The characteristics of the fatigue protocols were as follows: (i) control protocol: no training, (ii) moderate-fatigue protocol: 5 sets of the SMS exercise at 70%1RM performing half the maximum possible number of repetitions, and (iii) high-fatigue protocol: 5 sets of the SMS exercise performed to failure against the 70%1RM. Post-session declines in 1RM (p < 0.001), L₀ (p = 0.001) and A_line (p < 0.001) were the greatest after the high fatigue protocol, followed by the moderate fatigue protocol and finally the control protocol. Changes in v₀ did not differentiate between the fatigue protocols (p = 0.325). The post-session percentage change in 1RM was significantly correlated with the percentage change in A_line (r = 0.832) and L₀ (r = 0.764), but not with the percentage change in v₀ (r= -0.012). These results suggest that L-V relationship variables offer a highly sensitive and practical solution for fatigue monitoring. Trial registration: ClinicalTrials.gov, NCT07307963 (First posted: 27/11/2025; retrospectively registered).

This study examined the effects of varying rest periods on 20 m sprint performance following a single sled push with 50% of body weight (BW). Eighteen male participants from Istanbul Gelisim University voluntarily took part. On the first day, participants performed an 18 m sled push with 50% BW, followed by 10 and 20 m sprints conducted randomly after 15 seconds, 1-minute, and 3-minute recovery times. On the second day, participants performed three sprints at the start, followed by sled pushing and recovery periods of 5, 7, and 9 minutes in random order, after which 10 and 20 m sprint times were measured. The analysis revealed a significant decline in 20 m sprint performance after 15 seconds of rest compared to baseline (p < 0.001, η² = 0.317). However, performance improved significantly with 3 minutes of rest, returning to levels close to baseline (p > 0.05). The results indicated that a single sled push with 50% BW did not acutely enhance sprint performance via the post-activation potentiation (PAP) effect. Furthermore, it was observed that the 18 m sled push exercise had no detrimental impact on 20 m sprint performance after recovery periods of 3, 5, 7, or 9 minutes. In conclusion, coaches can incorporate a 3-minute recovery period following sled pushing with 50% BW as part of a complex training method, ensuring sufficient recovery for subsequent sprint exercises.

Bu araştırmanın amacı 1 jokerli ve 2 jokerli küçük alan oyunlarının jokersiz oyunlara göre ivmelenme, yavaşlama, farklı hız aralıklarında yapılan koşu mesafeleri, maksimal kalp atım hızının %80-90-100’ünde geçirilen toplam süre üzerine etkisini incelemekti. Araştırma 4 hafta süre ile haftada 1 gün olacak şekilde tasarlandı. Familirizasyon oturumu sonrasında, 24x36 m saha ölçülerinde 4 dakika süre ile rastgele bir seçimle 1’er set 4’e 4, 4’e 4+1 ve 4’e 4+2 formatlarını içeren küçük alan oyunları oynatıldı. Anlamlılık alfa düzeyi olarak 0,05 olarak belirlendi. Yüksek yoğunluklu parametrelerde jokersiz oyuna göre 1 jokerli ve 2 jokerli oyunlarda anlamlı bir değişim gözlemlenmedi. Ancak, yavaşlama (-1.99-1.00 m/sn²), ivmelenme (-1.99-1.00 m/sn²), KAH dk. [atım.dk-1] ve KAH ort. [atım.dk-2] parametrelerinde 1 jokerli oyunda jokersiz oyuna kıyasla anlamlı sonuçlar gözlemlendi. İvmelenme (-1.99-1.00 m/sn²) parametresi dışında 2 jokerli oyunlarda 1 jokerli ve jokersiz oyunlara göre tüm parametrelerde istatistiksel olarak anlamlı düzeyde yüksek fiziksel ve fizyolojik bir parametrede artış meydana gelmediğini göstermektedir. Bu sonuçlar: (i) jokersiz oyunlara kıyasla 1 jokerli oyunlarda orta yoğunluktaki yavaşlama, ivmelenme ve ortalama kalp atım hızı verilerinde anlamlı ölçüde artışa neden olduğunu, (ii) jokersiz ve 1 jokerli oyunlara kıyasla 2 jokerli oyunlarının hiçbir parametrede anlamlı artışa neden olmadığı görülmektedir