The load-depended loss of vertical barbell velocity at the end of the acceleration phase limits the maximum weight that can be lifted. Thus, the purpose of this study was to analyze how increased barbell loads affect the vertical barbell velocity in the sub-phases of the acceleration phase during the snatch. It was hypothesized that the load-dependent velocity loss at the end of the acceleration phase is primarily associated with a velocity loss during the 1st pull. For this purpose, 14 male elite weightlifters lifted seven load-stages from 70–100% of their personal best in the snatch. The load–velocity relationship was calculated using linear regression analysis to determine the velocity loss at 1st pull, transition, and 2nd pull. A group mean data contrast analysis revealed the highest load-dependent velocity loss for the 1st pull (t = 1.85, p = 0.044, g = 0.49 [−0.05, 1.04]) which confirmed our study hypothesis. In contrast to the group mean data, the individual athlete showed a unique response to increased loads during the acceleration sub-phases of the snatch. With the proposed method, individualized training recommendations on exercise selection and loading schemes can be derived to specifically improve the sub-phases of the snatch acceleration phase. Furthermore, the results highlight the importance of single-subject assessment when working with elite athletes in Olympic weightlifting.

An Institutional Review Board (IRB)-approved study was conducted to investigate the effects of the Tsunami Bar® (TB), a flexible barbell, on ground reaction force (GRF) production and muscle activity in the quadricep, hamstring, and gluteal muscle groups during phases of the squat exercise and compare the effects to the effects to using a rigid barbell (RB). A two-by-two repeated measures Analysis of Variance (ANOVA) test was used to compare the results. Descriptive statistics showed significantly higher GRFs for the TB during the unweighting phase, significant differences in GRFs between speeds for each phase, significantly higher forces on average with the RB during the breaking and propulsive phases at the 90 beats-per-minute (bpm) speed, and significantly higher muscle activity with the RB at the 60-bpm speed. A linkage to the beneficial effects of the TB seen in literature was seen with familiarity with the TB.

För att kunna prestera bra under fysiskt krävande ishockeymatcher krävs det att spelarna harhög maximal benstyrka och en hög explosiv förmåga. Bilaterala knäböj är en erkänd och välspridd övning för att förbättra power och muskelstyrka i benen. Unilaterala knäböj är än mersportspecifika för ishockeyn. Vid en isokinetisk rörelse är hastigheten förutbestämd ochdärmed konstant medan kraften kan förändras under rörelsen. De flesta isokinetiska systemhar varit designade för unilaterala isolerade övningar, men gällande isokinetiskaflerledsövningar så som knäböj tycks det inte finnas någon forskning om i nuläget.Studiens syfte var att undersöka effekten av sex veckors unilateral styrketräning (knäböj),antingen genom traditionell eller genom isokinetisk träning, på power i unilaterala ochbilaterala jump squats och 17.3 m sprinttid på is hos manliga juniorishockeyspelare.20 manliga ishockeyspelare på elitnivå, 18-19 år gamla, delades slumpmässigt in i två olikaträningsgrupper. Den ena gruppen (QG) utförde isokinetiska unilaterala knäböj i 1080Quantum med 110o vinkel i knäleden, medan den andra gruppen (SG) utförde traditionellaunilaterala knäböj i Smithmaskin med 110o vinkel i knäleden. Träningsperioden varade undersex veckor. Båda grupperna genomförde för- och eftertester bestående av sprinttest på is ochpeak power för unilaterala och bilaterala jump squats.QG visar en signifikant förbättring i peak power utfört på två ben (p=0,004). SG visar ensignifikant förbättring i unilaterala knäböj utfört på höger ben (p=0,018). QG hade en tendenstill signifikant förbättring i issprint (p=0,059).Isokinetiska unilaterala knäböj i Smithmaskin med en koncentrisk hastighet på 0,2meter/sekund och en excentrisk hastighet på maximalt 4,0 meter/sekund och en maximalkraftinsats är ett effektivt sätt att förbättra power på två ben och eventuellt också för attförbättra sprinthastigheten vid issprint för ishockeyspelare. Om isokinetiska unilaterala knäböjär en effektivare metod för att förbättra power jämfört med traditionella unilaterala knäböj iSmithmaskin med maximal hastighet är det svårt att dra slutsatser om från denna studiesresultat. / Ice-hockey are physically demanding. To be able to perform during a game it is required thatthe players have a high maximum leg strength and power. A bilateral squat is a valid and widespread exercise for improving muscle strength and power in the legs. Even more specific forice-hockey is the unilateral squat. During an isokinetic movement the velocity is pre-set andtherefore constant, while the force can be altered during the movement. Most isokineticsystems have been designed for unilateral training, but in terms of isokinetic multi-jointexercises, such as the squat, there seems to be no research until this day.The purpose of this study was to examine the effect of six weeks unilateral strength training(squat), either through traditional or isokinetic training, on power-output and 17.3 m sprinttime on ice among male junior ice-hockey players.20 elite male ice-hockey players, 18-19 years of age, was randomly divided in two differenttraining groups. One group (QG) did isokinetic unilateral squats in 1080 Quantum, with anangle of 110o degrees in the knee joint. The other group (SG) did traditional unilateral squatsin a Smith-machine, also with an angle of 110o degrees in the knee joint. The period oftraining was set to six weeks. Both groups participated in pre- and post-tests consisting ofsprint on ice and peak power in unilateral and bilateral jump squats.A significant improvement was seen with QG in peak power performed on both legs(p=0,004). SG had a significant improvement in unilateral squat performed on the right leg(p=0,018). A tendency to significant improvement was seen with QG in the ice-sprint(p=0,059).Isokinetic unilateral squat in a Smith-machine with a concentric velocity set to 0,2m/sec andan eccentric velocity set to 4,0m/sec with a maximum force is an effective exercise toimprove power-output on two legs, perhaps also to improve sprint ability on ice, among icehockeyplayers. It is difficult to draw conclusion about the results from this study whetherisokinetic unilateral squats is an effective method to improve the power compared totraditional unilateral squats in a Smith-machine with maximum speed.