Assessing your performance after your row requires you to somehow internalize and hold onto suggested changes for your next outing – then try to implement them with no real idea of whether you are doing it right. With real-time technical feedback and effort measurement, you can make sure you're hitting your targets for technical proficiency and training effectiveness when you need it most: while you're rowing.Quantifies Technique
Rowing faster is a game of increments – "quicker catch", "more compression", "less layback", "longer leg drive". Getting a feel for these subjective concepts on the water can take hundreds of hours. By quantifying catch, finish, and force application into simple numerical targets, technical changes become much easier to achieve and maintain.Measures Training Effort
Achieving peak fitness requires a "just right" training load, and the EmPower Oarlock takes the guesswork out of determining training effort. By quantifying work, power, and heart rate, you can consistently perform within suggested training zones to maximize physiological training benefits.
View your athletes' technique and output while they're rowing. Just stay within shouting distance of your athletes to see their real-time technical and effort measurements on a SpeedCoach GPS 2.So much more than just power
Everyone knows that erg power does not always translate to boat speed. Understand WHY and help every rower apply their personal best to the oar. Synchronize crew power application for maximum effectiveness. Combine work measurement with heart rate targets to develop efficiency.Set Clear Targets for your Athletes
Supplement your words and drills with measurable targets for each rower's technique and effort.
"Sit up at the catch" becomes "catch at 55°."
"Row half-pressure" becomes "stay within 150-175W."
Review workout data on the SpeedCoach to establish targets and monitor your athletes' performance against them. For even further insight, download the session and export to .csv to analyze and chart per-stroke data in a spreadsheet.
A longer stroke through the water yields a faster boat. Ensure you are hitting target CATCH ANGLES while minimizing SLIP in order to maximize potential boat speed.
Catch timing in team boats is highly dependent on all athletes catching at the same position. Use target CATCH ANGLES to quickly improve timing.
Finishing too short limits potential speed. Finishing too long slows the boat and wastes effort. Finding the proper finish length is tricky business which typically requires years of practice. Quickly optimize the finish with a balance of long FINISH ANGLES and minimal WASH.
Train more effectively by building your training plan around power. With real-time power feedback, you’ll be able to stay in the proper training zone with every stroke to maximize the physiological benefit of your workout.
The Classic mode is structured to always display stroke rate and split, the two key boat performance measures. Two additional flex fields offer the user any of the following metrics:
Combine any of these measurements you need for your workout, and have the ability to change them at the press of a button.
The skill screens are designed to focus on a particular skill:
Each skill screen shows preselected measurements which focus the rower on elements most relevant to improving that aspect of the stroke.
"You certainly have something there that athletes will like! Your system is actually quite a good help for us at this stage. Everything works so easily and without changing anything on the boat, it is indeed helping us!"
This system helped us so much in becoming better technical rowers. We were able to set up our foot stretchers to exactly match the angles at the catch and finish together. Seeing angles, slip, wash, and force measurements made us work on every stroke to be longer, more efficient, and faster. This is the best tool for rowers since the invention of the SpeedCoach.
"I wish I had the EmpPower Oarlock before my last race. I would have been so much faster!"
"It makes rowing more intellectual, conscious, better control. What we feel is very different from what we really do. This measurement tool is objective."
The EmPower Oarlock is the result of a collaboration between NK and Valery Kleshnev, founder and director of BioRow. BioRow is a rowing biomechanics research and consultancy firm known for producing both in-depth rowing technique analysis and dozens of medals in international competitions. NK has worked with Dr. Kleshnev since 2014 to merge BioRow approaches to measuring and quantifying complex rowing biomechanics with NK's industry-leading rugged rowing technology and user-friendly SpeedCoach GPS. NK will continue to work with Dr. Kleshnev to take full advantage of BioRow technology, knowledge, and analysis tools as the EmPower Oarlock progresses.
The EmPower Oarlock core is a specially designed load cell incorporating multiple strain gauges. The force of the oar during the drive on the face of the oarlock deforms the load cell, generating a strain measurement. This measurement is converted to a Force (Fgate), based on factory calibration values. The Wheatstone Bridge strain gauge configuration helps compensate for temperature variations.
Force at the handle (Fhandle) is calculated using the equation shown, and is a function of the oar length, inboard length, location of force on the handle and location of force on the blade.
Sculling: a=6cm | b=22.5cm
Sweep: a=15cm | b=27.5cm
Work is force times distance. In rowing, work per stroke is the average force times the arc length of the oar's travel. We calculate this by integrating work measurements over very short periods of time during the drive. For these short intervals, we multiply the average force times the arc length covered by the oar handle. Work per Stroke is the sum of these work measurements during the drive.
Power is work per unit of time. In rowing, power is the Work per Stroke divided by the Time per Stroke. While we use Work per Stroke as calculated on the drive, we use the Time per Stroke for the entire stroke cycle. This is done to account for physiological recovery which occurs during the stroke cycle, whereas the work is done primarily on the drive.
1. The catch is defined as the location where the oar changes direction.
2. Lock occurs when the force reaches 200N for sweep or 100N for sculling. Slip is the difference between Catch and Lock angles.
3. The location of Peak Force is the angle at which the maximum force occurs during any given stroke.
4. Unlock occurs when the force drops below 200N for sweep or 100N for sculling. Wash is the difference between Unlock and Finish angles.
5. The finish is defined as the location where the oar changes direction.
6. An angle of 0° is defined as when the oar handle is perpendicular to the boat. By convention, the oar handle rotated toward the stern is considered a negative angle (typical for the catch), and the oar handle rotated toward the bow is considered a positive angle (typical for the finish).
EmPower Oarlock data is displayed on a SpeedCoach GPS 2 with Training Pack. Each oarlock is wirelessly paired with its own SpeedCoach for athlete or coach viewing. Viewing distance is approximately 100’ line of sight from oarlock to SpeedCoach. At launch, the SpeedCoach will support one EmPower Oarlock, and scullers have the option of displaying raw effort-related measurements or doubling them to show total work and power. The SpeedCoach can be simultaneously paired with an NK heart rate belt to aid in developing physiologically efficient rowing.
Wireless connectivity is via Bluetooth® Low Energy. Data download is accomplished using NK LiNK for Windows or Mac OSX and an NK USB Dongle. Selected sessions can be exported from LiNK to an Excel compatible CSV file for viewing per-stroke data. Sessions can also be exported to a .fit file containing boat performance, heart rate and power data that is compatible with 3rd party apps such as Training Peaks and Strava.
EmPower Oarlocks are available for sweep and sculling and use bushings to accommodate various pin sizes. Be sure to order according to your rowing style and boat’s pin diameter. Bushings can be replaced if the oarlock is moved to a boat with different sized pins and if they become worn.
Currently, the EmPower Oarlock does not fit on standard Fluidesign, WinTech cup-style, and Empacher cup-style brackets. We are actively working with the boatbuilders mentioned to offer solutions for their customers moving forward.
The EmPower Oarlock is powered by a single AA battery, easily accessed with a sealed flip-lock door on the back of the oarlock. For most cost-effective use, we recommend rechargeable NiMH batteries such as Panasonic Eneloop® and Eneloop® Pro or Maha Powerex. Rechargeable AA's can be expected to provide 8-20 hours of operation depending on capacity, and multi-packs make it easy to have fresh batteries standing ready to use. For disposable batteries, we recommend Energizer Ultimate Lithium batteries, which will provide roughly double the run time of rechargeable batteries. We do NOT recommend the use of standard alkaline batteries. Particularly if they become damp when stored or installed, alkaline batteries are prone to leaking and the highly corrosive acid will destroy the EmPower Oarlock's electronics. Damage from leaking batteries is not covered under warranty. The oarlock automatically shuts down after 10 minutes without connection to a SpeedCoach.
The EmPower Oarlock is designed and built to be your everyday oarlock. It has a waterproof rating of IP67, which is defined as submersion up to 1m deep for up to 30 minutes. It also passes impact testing according to MIL-STD-810G, Transit Shock, Method 516.5, Procedure IV. This means it can withstand the typical impact you would expect to encounter when carrying a boat in and out of a boathouse. The oarlock can be operated from 32 to 131°F and 5-95% non-condensing humidity. It should be stored in a temperature range of -22 to 140°F.
Installing a brand new EmPower Oarlock typically takes about 10 minutes. We have created a short video series to walk you through the installation steps.
Step 1 - Introduction (3:01 minutes)
Step 2A - Installing on a Standard Pin (3:45 minutes)
Step 2B - Installing on a C-Cup Bracket (2:56 minutes)
Step 3 - Pairing (1:41 minutes)
Step 4 - Configuration (2:40 minutes)
Step 5 - Calibrating your Oarlock (5:03 minutes)
To maximize the value and flexibility of your rowing electronics investment, the EmPower Oarlock works with any SpeedCoach GPS 2. To support the EmPower Oarlock, the SpeedCoach must have Training Pack with firmware version 2.12 or higher. If you have an earlier version of firmware, you can update your firmware at no charge. If you do not have the Training Pack, you can purchase an upgrade. Installation of updates and upgrades requires a Bluetooth Low Energy USB Dongle. If you have any other NK performance monitor, you can trade it in under our Trade-In, Trade-Up Program.
The oarlock measures both the angle of the oarlock and the force being applied to the face of the oarlock. These measurements are taken 50 times per second and are then used by the oarlock to calculate per-stroke parameters which are transmitted to the SpeedCoach wirelessly. These measurements are ones that have been proven to be most helpful in evaluating and improving rowing effectiveness:
|Catch Angle||Angle of the oarlock when direction of motion reverses from recovery to drive direction.||Degrees of angle|
|Slip||Angle degrees traversed by the oarlock before the force exceeds 100 Newtons - a threshold below which the work being done on the oar is doing relatively little to increase the speed of the boat.||Degrees of travel/arc|
|Finish angle||Angle of the oarlock when direction of motion reverses from drive to recovery direction||Degrees of angle.|
|Wash||Angle degrees traversed by the oarlock after the force drops below 100 Newtons – a threshold below which the work being done on the oar is doing relatively little to increase the speed of the boat.||Degrees of travel/arc|
|Length||Total degrees traversed by the oarlock between catch and finish.||Degrees of travel/arc|
|Effective Length||Total degrees traversed by the oarlock between the 100 newton slip and wash thresholds.||Degrees of travel/arc|
|Peak Force||The maximum force applied to the oarlock face at any point in the stroke.||Newtons|
|Peak Force Angle||The degrees of angle at which the peak force occurred in the stroke.||Degrees of angle|
|Stroke Force||The force applied to the oarlock face averaged over the full stroke.||Newtons|
|Work per Stroke||The average force times the length of the stroke. Work measures the effectiveness of each stroke.||Joules|
|Power||The rate of work being output. Power can be increased by doing more work per stroke, or taking more strokes per minute.||Watts (Joules per Second)|
The magnet plate installed below the oarlock creates a magnetic field which is sensed by a magnetometer inside the oarlock. The calibration routine uses a provided calibration artifact, which is basically a protractor that clips onto the magnet bar, to "teach" the oarlock what it will sense at certain angles, ensuring that it provides measurements that are accurate for your oarlock/pin/rigger setup. Angle is displayed with whole degree resolution and is accurate to +/- 2 degrees.
The oarlock is installed in exactly the same way you would replace the oarlock on your boat, or remove it to change pitch bushings, and you'll need the same tools your boat would require for that task (such as 7/16", 10mm and/or 13mm wrench and/or screwdriver for backstay adjustment). It can typically be installed in 5-10 minutes, particularly with familiarity. A 2.5mm Allen wrench for securing the magnet bar is included with the oarlock. It is helpful to use a long straight edge, such as a 6ft level, for aligning the magnet bar and zeroing the oarlock angle.
Typical battery life in the Oarlock is 10-25hrs, depending on the battery and ambient temperature. We recommend high quality Lithium disposables or Low Self Discharge rechargeable NiMH batteries for more economical use. We do NOT recommend use of alkaline batteries because they are prone to leaking, particularly in a humid environment, and A LEAKING BATTERY WILL DESTROY THE OARLOCK ELECTRONICS AND IS NOT COVERED UNDER WARRANTY! Here are some batteries we tested, along with the duration they ran under typical use at 75°F:
|Energizer Ultimate Lithium||25hrs|
|Duracell Duralock Rechargeable 2500mAh||15hrs|
|Eneloop Pro Rechargeable 2450mAh||15hrs|
|Energizer Max Alkaline||15hrs (NOT recommended!)|
|Tenergy Rechargeable 2600mAh||14hrs|
|Energizer Power Plus Rechargeable 2300mAh||13hrs|
|Energizer Industrial Alkaline||13hrs (NOT recommended!)|
|Duracell Alkaline 1500mAh||11hrs (NOT recommended!)|
|Energizer Universal Rechargeable 1500mAH||10hrs|
The range from an oarlock to paired SpeedCoach is approximately 100ft (30m). Simply hold or mount the SpeedCoach in a nearby motorboat to view oarlock measurements. Because each Oarlock pairs to a single SpeedCoach, you will need a SpeedCoach for each seat you wish to view. We recommend installation of SpeedCoach Surface Mounts in the launch to secure the SpeedCoach units for viewing.
We have tried to balance viewing flexibility with ease of operation by providing two display modes:
"SKILL" mode offers pre-configured data screens that are fast and easy for athletes to use to focus on particular aspects of the stroke. The preconfigured SKILL screens are CATCH, FINISH, LENGTH, WORK, POWER.
"CLASSIC" display mode offers full flexibility to choose any data in any of the four SpeedCoach windows and is ideal for rowers and coaches who are interested in creating their own preferred combinations. For example, it is possible to see how boat speed is impacted by catch and finish angle. Or, monitor heart rate and power while maintaining rating. In CLASSIC mode you have the option of freezing the top windows to Rate and Split and changing only the bottom two, or allowing all four windows to flex.
Force curves were made available in early rowing analysis systems because they are the most basic representation of the actual analog data from the force sensor, with no analysis applied. As a result, they're familiar, but that doesn’t mean they're ideal. Even after years of looking at and coaching with force curves, there is not much agreement in the sport about what makes a "good" force curve. (Lots of opinions, but not much agreement!) Also, it is challenging for athletes to use force curves as a target for changing their rowing, particularly without a clear target also represented on screen. We have chosen to present primarily numerical data that breaks the stroke down into clearly understood elements because we have demonstrated to ourselves, and many other coaches and athletes, that simple numbers are much easier to focus on when attempting to make changes or assess progress.
Because the EmPower Oarlock logs five key elements each and every stroke (catch angle, slip, peak force, peak force location, wash and finish angle), we are also able to present a clear "picture" of the stroke very similar to a force curve which we call a "Stroke Profile".
When charted using a simple Excel template, the Stroke Profile illustrates these key characteristics of one or more rower. In the example below, four scullers were evaluated during 20' session. We can see that Rower #2 is probably rigged too far into the bow (see their shallow catch angle and deep finish angle). We can also see that Rower #2 has their peak force occurring later in the drive than the other three. The coach can now provide Rower #2 with a target Peak Force Angle of -10 to -20° in order to better match the other rowers in the boat. Rower #2 can monitor himself as he rows future sessions.
With our focus on simplicity of installation, pairing and understandability, the initial release of the system is a one-to-one pairing between oarlock and SpeedCoach. Every oarlock needs a dedicated SpeedCoach to view and log its measurements. The SpeedCoach is hardware capable of pairing to multiple oarlocks, and we will offer this option as a firmware update in the future.
While it is absolutely true that all scullers have differences in their stroke between their left and right hands, these differences (a) cannot be TOO great or the boat would never go straight; and (b) are generally smaller in their impact on boat speed than the larger elements which can be captured on either side. When in sculling mode, the SpeedCoach doubles the Work and Power values obtained from the single Oarlock so the effective athlete output is shown. We are in part choosing to release the EmPower Oarlock for sculling as a one-to-one system to learn more about the typical combinations of measurements preferred by scullers so we can create a simplified and manageable user interface for displaying the MANY values available when you double the number of Oarlock measurements to be displayed. We promise you will see that the system is incredibly powerful with only one Oarlock as soon as you try it. Note that you can also swap sides occasionally to compare results because the Oarlock is so quick and easy to install and can be used on either side.
The initial release of the system does not allow pairing of SpeedCoach units for timing comparisons in team boats. However,one of the main contributors to poor timing is inconsistent catch and finish angles between rowers. By coordinating all rowers to hit the same angles, timing is generally self-corrected.
There are rough guidelines for what to expect (-65 and +40 for sculling, -75 and 45 for sweep), but no "perfect angles" for every situation. Angles will differ based on unchangeable variables, such as sweep vs. sculling and the height and arm span of the athlete, and changeable ones, such as rowing style, foot stretcher location, spread/gearing, and inboard. In fact, knowing angles is what allows coaches and athletes to adjust and test these variable parameters. The goal is having each athlete hit angles that maximize their effectiveness, and in team boats, having all athletes hit the same angles as closely as possible. The other measurements provided by the EmPower Oarlock assist you in making these evaluations: slip, wash, length and effective length, as well as trial and error combined with assessing the results.
Our partners at BioRow have been measuring athletes and compiling representative data for over twenty years. This Oarlock Reference Values Table summarizes representative ranges for many of the values provided by the EmPower Oarlock.
We adopted with the approach employed by Valery Kleshnev of BioRow, which is to use a set threshold. Clearly, that set threshold may not truly define "slip" and "wash" as we think of it for a smaller, lighter, or less powerful athlete. This threshold is also pretty much irrelevant if you’re paddling as much of the stroke will be below this value. However, if you think of these measurements more as a relative target than as an absolute target, the fixed threshold is simple and effective. For example: "I tend to lay back too far and lose my grip on the water. When I do that, my wash value is 18. When I keep my core engaged and shorten my finish slightly, my wash drops to 10 or 11 and my speed increases. I'm going to try to keep my wash value below 12 at steady state."
This discussion, in general, points out our philosophy with this product. We may not be starting with 100% perfect measurements, perfectly executed. There has simply not been broad enough access to rowing biomechanics data like this to determine the absolute best way to measure everything on day one. We teamed with Dr. Kleshnev and BioRow to ensure we had a strong, validated starting point with measurements that have helped him coach many athletes to world-record times. But, we are also sure we and our customers are going to learn new approaches from expanded use of this system, which is why we are anxious to get it on all sorts of boats with all sorts of athletes. We have been using it in our own rowing and coaching, and we have seen first-hand that these measurements make sense and work in practice. And, both the Oarlock and the SpeedCoach can be updated in the field as we continue to make improvements in the future. Alternatives here would be to make these a user-settable threshold value, or to define them as a percent of peak force. We may test these approaches in the future.
We have put a huge amount of effort into making sure each sensor is accurately calibrated and provides consistent readings in all situations and conditions. We have not yet encountered a situation where the measurements don't make sense.
The only C-cup rigger we have found that does NOT work is the standard Fluid Design cup. It is slightly too shallow to accommodate the electronics on the back of the oarlock. Fluid Design is developing a replacement that will accommodate the oarlock. We have tested the EmPower Oarlock with Hudson, Filippi and other brands and it fits with no adjustment.
The weight difference is small (170g sculling, 188g sweep) and unnoticeable once the weight of the rower is added to the boat. However, the weight WILL make an unloaded single or double tip in the direction of the oarlock, so some attention must be paid when placing the boat in the water. Again - if this proves annoying to people, we'll experiment with a weight bar that could be added to the other oarlock.
In all three systems, WORK is calculated as FORCE over the LENGTH of the stroke. POWER is WORK over time. These are measured as the actual output of the athlete applied to the oar/handle and should be fairly equivalent. Work done by the athlete on the slide is not measured in either case, although it does affect the athlete/boat/oar system. Note that calories on the C2 erg are calculated differently as there is a "per stroke" addition for calories burned going up the slide standardized for a 175 pound male athlete.
No current plans for a V2. Will support this with future software updates. There will undoubtedly be changes at some point - we've generally not stood still with our products - but this one has the smarts and connectivity to be updated for quite a long time.
At a 2:30 you are definitely rowing hard enough that you will see slip and wash numbers that are reflective of your technique, and respond to changes in a relevant way. Your "wash" arc degrees below 100N are likely to be greater than a tall heavyweight sculler's, but reducing the value will indicate a more effective finish.
That is actually the beauty of these values vs. speed, particularly where wind is concerned, or where you are using GPS speed on moving water: they are measuring the work YOU are doing in the boat to move the boat through the water. So, while your GPS speed may change with current, or your water speed may change with wind, work and power are accurate measures of your output and will be consistent indicators of your effort and effectiveness. (Slip and wash will be revealing indicators of how your technique changes with headwind and tailwind.)
Users need to download the latest revision of the LiNK application for MacOS X or Windows (version 1.27 or higher) in order to export the Oarlock data. If you are just getting summary data in the export file, you most likely have an older version of the LiNK application. You can get the latest version through our site here. Please note that you currently can not download the Oarlock data through our LiNK mobile applications. We are working to include integration of the Oarlock data with the mobile applications in the future, but do not have a timetable as of yet.
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