The biomechanics for human muscles can drastically be affected by grip position. Grips can change in many ways, it can be wide, narrow, neutral, pronated, and/or supinated. With all these variations it can be clear certain grips will affect different muscles. In this report analysis, two lab reports will be used. The first lab report is “Effects of Grip Width on Muscle Strength and Activation in the Lat Pull-Down” by Andersen, V, Fimland, MS, Wiik, E, Skoglund, A, and Saeterbakken, AH. The second report is “Relationships between Mechanical Variables in the Traditional and Close-Grip Bench Press” by Dr. Robert G. Lockie. These two reports will be determining how grip can affect certain exercises. 

In the first report, they will be using the lat pull-down exercise to show if different grips activate different muscles. The lat pull-down is a back exercise that primarily targets the  latissimus dorsi but it also activates the upper back such as the trapezius muscle with bicep and forearm activation as well. This  exercise has similarities to movements in sports such as climbing,  performing the rings in gymnastics, and different strokes in swimming. In the fitness community, there is a common belief that a wider grip on the lat pull-down will activate more of the latissimus dorsi muscle than a narrow grip. The second report discusses the mechanical variables between a close grip bench press(CGBP) and a neutral grip bench press(NGBP). Bench press is a very commonly used exercise for optimal activation of the chest, triceps, and shoulders. They are trying to discover the difference between CGBP and NGBP mechanical performance. The abstracts for both reports basically summarized the experiment.

In the beginning of the reports, the introduction was the first part to describe the first steps in these experiments. In the first report, it elaborated about how the lat pull-down exercises are performed and explained how their background information comes into play in this experiment. Multiple reports were brought up causing them to say how there is conflict between the studies, and how other studies did not access the grips for lat pull-downs in a proper manner. The main takeaway of the introduction is to compare the 6RM load and electromyographic (EMG) activity in the lat-pull down using 3 different grip widths. For the second report, they had a similar format as the first one. In the start of the introduction, they had a in depth analysis on how the participants will be performing the exercise and what specific muscle groups will be used predominantly in the experiment. They explained that the NGBP is more suitable for most of the participants in the experiment rather than CGBP because they can push the greatest amount of weight that way. It explained the mechanical variables they will be measuring such as lift distance and duration, work, peak and mean power, force, and velocity.The main takeaway from this introduction is  there would be significant differences in the load and the mechanical variables between the TBP and CGBP. It was further hypothesized that these variables for the TBP would correlate with those from the CGBP.

The method is the next part for all lab reports. In both labs, they discussed their experimental approach to the perceived hypothesis. They explained who and what our participants for the experiment are going to be. The subjects for both experiments are  relatively similar. It had men in the ages between 18-24, nearly the same height and weight with a relatively healthy lifestyle and no negative medical history of any kind. They both have low amounts of subjects which isn’t a good sign for an effective experiment. Both having under 100 subjects in their experiment causes inaccurate results. Their experimental approach consists of performing the exercise with different grips. For the lat pull-down experiment, the subjects were using electromyographic measurements, which is used as a diagnostics tool for identifying neuromuscular diseases and/or disorders of motor control. But in this case it will be used to measure the amount of back muscle activation that occurs. For the second report, they used a 1 repetition max to measure the difference between CGBP and NGBP. 

In the design and procedure, The lat pull-down experiment made its subjects perform the exercise for multiple sets to fully warm up the muscles. The subjects eventually reach a maximum load for the exercise and in that weight, they measure the activation between the 3 different grips. They tested all 3 grips, and with the electromyographic measurements they had an effective way to measure how the muscle reacts to all three different grip changes. In the bench pressing experiment, they used a standardized bench platform with a stiff bar barbell. They had all the participants to actively stretch and begin warming up for the bench press. They gave the subjects 3 min in between each set of warm up to properly rest. Eventually the subjects built up to a 1 repetition max on the NGBP until they were unable to perform another because of the overload of weight. After they  finish their max NGBP, the subjects proceed to perform the CGBP. 

As the experiment passes on and they perform the experiments they have to do the statistical analysis. For the lat pulldown, they measured the 3 grip width which is independent and the dependent is the electromyographic measurements and the specific load for each subject. They conjugated a formula to calculate which had the most activation. The second experiment used the Statistics Package for Social Sciences Version 24.0. They Used a correlation coefficient to determine peak and mean power, force, and velocity. Once they explain the statistics for the experiment. They now have the scientific data to create the result. 

Both reports consisted of data focused results. For the lat pull-down experiment, Comparing the EMG activity of the whole movement of the 6 repetitions (concentric and eccentric phases) revealed similar muscle activation of all muscles for the 3 grips.  They broke down each grip in a very detailed manner. For instance, the narrow grip explained how it had the greatest effect on the bicep muscle on the arm and the least effect on the latissimus dorsi. As they go on explaining how they compared the EMG activity amongst all grips to see the greatest activation for overall use on the back. For the bench report it also consisted of a large number of statistics to back up their claims about the results. There was a significant difference between the grip width for the TBP and CGBP, with a very large effect. A greater load was lifted in the TBP, although this only had a small effect. Lift duration was longer for the TBP, and mean force was greater; however, both of these effects were small. Peak power, peak velocity, and mean velocity were greater for the CGBP, which had moderate, large, and small effects. They displayed a table showing all the data for each grip to show where the grips were at its best. The overall result was that the NGBP has overall the greatest amount of impact on raw power and overall ability to push maximal amount of weight, but the CGBP has the greatest impact on athletic performance. So they concluded that NGBP is better at displaying an act of strength and CGBP is more to actually build the power to perform in athletic settings.

After both reports concluded their individual results they began discussion. Both discussions were the longest part of the report. It connected all the lab variables into one which really molded their final conclusions. In the lat pull-down report, the discussion consisted of comparisons of each of the grip results. They concluded in the report “There was no major difference in activation for latissimus dorsi, biceps brachii, infraspinatus, or trapezius when performing 6RM in the anterior lat pull-down with narrow, medium, and wide anterior grip widths. However, the 6RM load lifted was lower using a wide compared with a small or medium grip. Still, there was some weak evidence that a medium grip may have some advantages over narrow or wide grip.” For the bench press report they had similar format as the lat pulldown. They compared both grips and concluded that “The results indicated that there were similarities in the mechanics of the TBP and the CGBP”. Which basically finalized the discussion aspect of the report. 

They both had an acknowledgement which consisted of thanking the participants and researchers. They both also stated that the experiment wasn’t funded by any outside source and how none of the authors had conflict of interests. At the end both must reference any outside work used to help out with the experiment. 

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